diff --git a/.template-lintrc.js b/.template-lintrc.js
index b45e96f..02bee12 100644
--- a/.template-lintrc.js
+++ b/.template-lintrc.js
@@ -1,5 +1,9 @@
 'use strict';
 
 module.exports = {
-  extends: 'recommended'
+  extends: 'recommended',
+
+  rules: {
+    'simple-unless': false
+  }
 };
diff --git a/app/components/add-contributor/component.js b/app/components/add-contributor/component.js
index 32800c1..7e3b821 100644
--- a/app/components/add-contributor/component.js
+++ b/app/components/add-contributor/component.js
@@ -2,7 +2,6 @@ import Component from '@ember/component';
 import { and, notEmpty } from '@ember/object/computed';
 import { inject as service } from '@ember/service';
 
-
 export default Component.extend({
   kredits: service(),
 
@@ -14,6 +13,7 @@ export default Component.extend({
   isValidURL: notEmpty('url'),
   isValidGithubUID: notEmpty('github_uid'),
   isValidGithubUsername: notEmpty('github_username'),
+  isValidGiteaUsername: notEmpty('gitea_username'),
   isValidWikiUsername: notEmpty('wiki_username'),
   isValid: and(
     'isValidAccount',
@@ -21,10 +21,11 @@ export default Component.extend({
     'isValidGithubUID'
   ),
 
+  inProgress: false,
+
   init () {
     this._super(...arguments);
 
-    // Default attributes used by reset
     this.set('attributes', {
       account: null,
       name: null,
@@ -32,8 +33,8 @@ export default Component.extend({
       url: null,
       github_username: null,
       github_uid: null,
-      wiki_username: null,
-      isCore: false
+      gitea_username: null,
+      wiki_username: null
     });
   },
 
@@ -53,17 +54,19 @@ export default Component.extend({
         return;
       }
 
-      let attributes = Object.keys(this.attributes);
-      let contributor = this.getProperties(attributes);
-      let saved = this.save(contributor);
+      const attributes = Object.keys(this.attributes);
+      const contributor = this.getProperties(attributes);
 
-      // The promise handles inProgress
-      this.set('inProgress', saved);
+      this.set('inProgress', true);
 
-      saved.then(() => {
+      this.save(contributor).then(() => {
         this.reset();
         window.scroll(0,0);
-        window.alert('Contributor added.');
+      }).catch(err => {
+        console.log(err);
+        window.alert('Something went wrong. Please check the browser console.');
+      }).finally(() => {
+        this.set('inProgress', false);
       });
     }
   }
diff --git a/app/components/add-contributor/template.hbs b/app/components/add-contributor/template.hbs
index 235c535..fe98c5f 100644
--- a/app/components/add-contributor/template.hbs
+++ b/app/components/add-contributor/template.hbs
@@ -1,13 +1,4 @@
 <form {{action "submit" on="submit"}}>
-  <p>
-    {{input name="is-core"
-            type="checkbox"
-            id="is-core"
-            checked=isCore}}
-    <label for="is-core" class="checkbox">
-      Core team member (can add contributors)
-    </label>
-  </p>
   <p>
     {{input name="account"
             type="text"
@@ -49,6 +40,13 @@
             value=github_username
             class=(if isValidGithubUsername "valid" "")}}
   </p>
+  <p>
+    {{input name="gitea_username"
+            type="text"
+            placeholder="Gitea username"
+            value=gitea_username
+            class=(if isValidGiteaUsername "valid" "")}}
+  </p>
   <p>
     {{input name="wiki_username"
             type="text"
@@ -58,7 +56,7 @@
   </p>
   <p class="actions">
     {{input type="submit"
-            disabled=(is-pending inProgress)
-            value=(if (is-pending inProgress) "Processing" "Save")}}
+            disabled=inProgress
+            value=(if inProgress "Processing" "Save")}}
   </p>
 </form>
diff --git a/app/components/contribution-list/component.js b/app/components/contribution-list/component.js
index c490f86..f85da1d 100644
--- a/app/components/contribution-list/component.js
+++ b/app/components/contribution-list/component.js
@@ -5,16 +5,16 @@ export default Component.extend({
   tagName: 'ul',
   classNames: ['contribution-list'],
 
-  // actions: {
-  //
-  //   veto (contributionId) {
-  //     if (this.contractInteractionEnabled) {
-  //       this.vetoContribution(contributionId);
-  //     } else {
-  //       window.alert('Only members can veto contributions. Please ask someone to set you up.');
-  //     }
-  //   }
-  //
-  // }
+  actions: {
+
+    veto (contributionId) {
+      if (this.contractInteractionEnabled) {
+        this.vetoContribution(contributionId);
+      } else {
+        window.alert('Only members can veto contributions. Please ask someone to set you up.');
+      }
+    }
+
+  }
 
 });
diff --git a/app/components/contribution-list/template.hbs b/app/components/contribution-list/template.hbs
index d53ad52..29a5760 100644
--- a/app/components/contribution-list/template.hbs
+++ b/app/components/contribution-list/template.hbs
@@ -1,5 +1,5 @@
 {{#each contributions as |contribution|}}
-  <li data-contribution-id={{contribution.id}} class={{if contribution.confirmed "confirmed" "unconfirmed"}}>
+  <li data-contribution-id={{contribution.id}} class="{{contribution-status contribution}} {{if contribution.vetoed "vetoed"}}">
     <p class="meta">
       <span class="recipient">{{user-avatar contributor=contribution.contributor}}</span>
       <span class="category {{contribution.kind}}">({{contribution.kind}})</span>
@@ -14,5 +14,12 @@
     <p class="kredits-amount">
       <span class="amount">{{contribution.amount}}</span><span class="symbol">₭S</span>
     </p>
+    {{#unless contribution.vetoed}}
+      {{#unless (is-confirmed-contribution contribution)}}
+        <p class="voting">
+          <button {{action "veto" contribution.id}} class="small danger">veto</button>
+        </p>
+      {{/unless}}
+    {{/unless}}
   </li>
 {{/each}}
\ No newline at end of file
diff --git a/app/components/contributor-list/template.hbs b/app/components/contributor-list/template.hbs
index 765ebd9..ec319e4 100644
--- a/app/components/contributor-list/template.hbs
+++ b/app/components/contributor-list/template.hbs
@@ -19,7 +19,7 @@
       <td colspan="2">
         <ul>
           <li>
-            <a href="https://testnet.etherscan.io/address/{{c.contributor.account}}" target="_blank" rel="noopener">Inspect Ethereum transactions</a>
+            <a href="https://rinkeby.etherscan.io/address/{{c.contributor.account}}" target="_blank" rel="noopener">Inspect Ethereum transactions</a>
           </li>
           {{#if c.contributor.ipfsHash}}
             <li>
diff --git a/app/controllers/index.js b/app/controllers/index.js
index 6361b3d..9c614c7 100644
--- a/app/controllers/index.js
+++ b/app/controllers/index.js
@@ -27,21 +27,21 @@ export default Controller.extend({
 
   actions: {
 
-    vetoContribution (/* contributionId */) {
-      // this.kredits.vote(proposalId).then(transaction => {
-      //   window.confirm('Vote submitted to Ethereum blockhain: '+transaction.hash);
-      // });
+    vetoContribution (contributionId) {
+      this.kredits.veto(contributionId).then(transaction => {
+        console.debug('[controllers:index] Veto submitted to Ethereum blockhain: '+transaction.hash);
+      });
     },
 
     confirmProposal (proposalId) {
       this.kredits.vote(proposalId).then(transaction => {
-        window.confirm('Vote submitted to Ethereum blockhain: '+transaction.hash);
+        console.debug('[controllers:index] Vote submitted to Ethereum blockhain: '+transaction.hash);
       });
     },
 
     save (contributor) {
       return this.kredits.addContributor(contributor)
-        .then((contributor) => {
+        .then(contributor => {
           this.contributors.pushObject(contributor);
           return contributor;
         });
diff --git a/app/helpers/contribution-status.js b/app/helpers/contribution-status.js
new file mode 100644
index 0000000..79e4bbb
--- /dev/null
+++ b/app/helpers/contribution-status.js
@@ -0,0 +1,20 @@
+import Helper from '@ember/component/helper';
+import { inject as service } from '@ember/service';
+import { alias } from '@ember/object/computed';
+
+export default Helper.extend({
+
+  kredits: service(),
+  currentBlock: alias('kredits.currentBlock'),
+
+  compute([contribution]) {
+    if (contribution.vetoed) {
+      return 'vetoed';
+    } else if (contribution.confirmedAt > this.currentBlock) {
+      return 'unconfirmed';
+    } else {
+      return 'confirmed'
+    }
+  }
+
+});
diff --git a/app/helpers/is-confirmed-contribution.js b/app/helpers/is-confirmed-contribution.js
new file mode 100644
index 0000000..0f63b76
--- /dev/null
+++ b/app/helpers/is-confirmed-contribution.js
@@ -0,0 +1,15 @@
+import Helper from '@ember/component/helper';
+import { inject as service } from '@ember/service';
+import { alias } from '@ember/object/computed';
+
+export default Helper.extend({
+
+  kredits: service(),
+  currentBlock: alias('kredits.currentBlock'),
+
+  compute([contribution]) {
+    return !contribution.vetoed &&
+           (contribution.confirmedAt <= this.currentBlock);
+  }
+
+});
diff --git a/app/services/kredits.js b/app/services/kredits.js
index 39e62af..15bb528 100644
--- a/app/services/kredits.js
+++ b/app/services/kredits.js
@@ -84,9 +84,10 @@ export default Service.extend({
         });
       }
 
-      function instantiateWithAccount (web3Provider, context) {
+      async function instantiateWithAccount (web3Provider, context) {
         console.debug('[kredits] Using user-provided instance, e.g. from Mist browser or Metamask');
         ethProvider = new ethers.providers.Web3Provider(web3Provider);
+        // const network = await ethProvider.getNetwork();
         ethProvider.listAccounts().then(accounts => {
           context.set('currentUserAccounts', accounts);
           const ethSigner = accounts.length === 0 ? null : ethProvider.getSigner();
@@ -162,10 +163,15 @@ export default Service.extend({
   },
 
   addContributor(attributes) {
+    if (attributes.github_uid) {
+      const uidInt = parseInt(attributes.github_uid);
+      attributes.github_uid = uidInt;
+    }
+
     console.debug('[kredits] add contributor', attributes);
 
-    return this.kredits.Contributor.add(attributes)
-      .then((data) => {
+    return this.kredits.Contributor.add(attributes, { gasLimit: 350000 })
+      .then(data => {
         console.debug('[kredits] add contributor response', data);
         return Contributor.create(attributes);
       });
@@ -215,12 +221,22 @@ export default Service.extend({
     console.debug('[kredits] vote for', proposalId);
 
     return this.kredits.Proposal.functions.vote(proposalId)
-      .then((data) => {
+      .then(data => {
         console.debug('[kredits] vote response', data);
         return data;
       });
   },
 
+  veto(contributionId) {
+    console.debug('[kredits] veto against', contributionId);
+
+    return this.kredits.Contribution.functions.veto(contributionId, { gasLimit: 300000 })
+      .then(data => {
+        console.debug('[kredits] veto response', data);
+        return data;
+      });
+  },
+
   getCurrentUser: computed('kredits.provider', function() {
     if (isEmpty(this.currentUserAccounts)) {
       return RSVP.resolve();
@@ -241,23 +257,30 @@ export default Service.extend({
     return this.proposals.findBy('id', proposalId.toString());
   },
 
-  findContributionById(contributionId) {
-    return this.contributions.findBy('id', contributionId.toString());
-  },
-
   // Contract events
   addContractEventHandlers() {
-    // Proposal events
+    this.kredits.Contribution
+      .on('ContributionVetoed', this.handleContributionVetoed.bind(this))
+
     this.kredits.Proposal
       .on('ProposalCreated', this.handleProposalCreated.bind(this))
       .on('ProposalVoted', this.handleProposalVoted.bind(this))
       .on('ProposalExecuted', this.handleProposalExecuted.bind(this));
 
-    // Token events
     this.kredits.Token
       .on('Transfer', this.handleTransfer.bind(this));
   },
 
+  handleContributionVetoed(contributionId) {
+    console.debug('[kredits] ContributionVetoed event received for ', contributionId);
+    const contribution = this.contributions.findBy('id', contributionId);
+    console.debug('[kredits] contribution', contribution);
+
+    if (contribution) {
+      contribution.set('vetoed', true);
+    }
+  },
+
   handleProposalCreated(proposalId) {
     let proposal = this.findProposalById(proposalId);
 
diff --git a/app/styles/_buttons.scss b/app/styles/_buttons.scss
new file mode 100644
index 0000000..8a6956a
--- /dev/null
+++ b/app/styles/_buttons.scss
@@ -0,0 +1,30 @@
+button, input[type=submit] {
+  display: inline-block;
+  padding: 0.6rem 2rem;
+  background-color: rgba(22, 21, 40, 0.6);
+  border: 1px solid rgba(22, 21, 40, 1);
+  border-radius: 3px;
+  color: $primary-color;
+  font-weight: 500;
+  text-transform: uppercase;
+  cursor: pointer;
+  letter-spacing: 0.1em;
+
+  &:hover {
+    background-color: rgba(22, 21, 40, 0.8);
+  }
+
+  &.small {
+    font-size: 0.8rem;
+    padding: 0.2rem 0.8rem;
+  }
+
+  &.danger {
+    color: $red;
+    background-color: rgba(40, 21, 21, 0.6);
+
+    &:hover {
+      background-color: rgba(40, 21, 21, 0.8);
+    }
+  }
+}
diff --git a/app/styles/app.scss b/app/styles/app.scss
index e33191c..d5e0f28 100644
--- a/app/styles/app.scss
+++ b/app/styles/app.scss
@@ -87,22 +87,6 @@ section {
   }
 }
 
-button, input[type=submit] {
-  display: inline-block;
-  border: 1px solid rgba(22, 21, 40, 1);
-  background-color: rgba(22, 21, 40, 0.6);
-  color: $primary-color;
-  border-radius: 3px;
-  font-weight: 500;
-  text-transform: uppercase;
-  cursor: pointer;
-  letter-spacing: 0.1em;
-
-  &:hover {
-    background-color: rgba(22, 21, 40, 0.8);
-  }
-}
-
 @media (min-width: 550px) {
   section {
     h2 {
@@ -111,6 +95,7 @@ button, input[type=submit] {
   }
 }
 
+@import "buttons";
 @import "components/topbar";
 @import "components/loading-spinner";
 @import "components/contributor-list";
diff --git a/app/styles/components/_contribution-list.scss b/app/styles/components/_contribution-list.scss
index c865532..71367b9 100644
--- a/app/styles/components/_contribution-list.scss
+++ b/app/styles/components/_contribution-list.scss
@@ -13,7 +13,7 @@ ul.contribution-list {
 
   li {
     display: grid;
-    grid-template-columns: auto 5rem;
+    grid-template-columns: auto 5rem 5rem;
     grid-row-gap: 0.5rem;
     padding: 1rem 1.2rem;
     background-color: rgba(255,255,255,0.1);
@@ -24,6 +24,16 @@ ul.contribution-list {
       border-top: 1px solid rgba(255,255,255,0.2);
     }
 
+    &.confirmed {
+      grid-template-columns: auto 5rem;
+    }
+
+    &.vetoed {
+      grid-template-columns: auto 5rem;
+      text-decoration: line-through;
+      opacity: 0.6;
+    }
+
     p {
       align-self: center;
       margin: 0;
@@ -33,14 +43,6 @@ ul.contribution-list {
       &.kredits-amount, &.voting {
         text-align: right;
       }
-
-      &.description {
-        grid-column-start: span 2;
-      }
-
-      &.voting {
-        grid-column-start: span 2;
-      }
     }
 
     span {
@@ -92,12 +94,6 @@ ul.contribution-list {
       color: $primary-color;
       margin-right: 0.5rem;
     }
-
-    button {
-      height: 2rem;
-      line-height: 2rem;
-      padding: 0 0.6rem;
-    }
   }
 
 }
diff --git a/app/styles/components/_proposal-list.scss b/app/styles/components/_proposal-list.scss
index 2599a0b..2527ad2 100644
--- a/app/styles/components/_proposal-list.scss
+++ b/app/styles/components/_proposal-list.scss
@@ -73,12 +73,6 @@ ul.proposal-list {
       color: $primary-color;
       margin-right: 0.5rem;
     }
-
-    button {
-      height: 2rem;
-      line-height: 2rem;
-      padding: 0 0.6rem;
-    }
   }
 
 }
diff --git a/package-lock.json b/package-lock.json
index b20efe9..cc8d49b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10911,9 +10911,9 @@
       }
     },
     "kredits-contracts": {
-      "version": "5.2.0",
-      "resolved": "https://registry.npmjs.org/kredits-contracts/-/kredits-contracts-5.2.0.tgz",
-      "integrity": "sha512-XS8PN01SEiSNDKUhH28KVmGJ7hS3HlhT+CsaAMgqvU9ACcE1Wizqd0AxoRutUmJkILic6W6bQQ5gRqSHcBpPBA==",
+      "version": "5.3.0",
+      "resolved": "https://registry.npmjs.org/kredits-contracts/-/kredits-contracts-5.3.0.tgz",
+      "integrity": "sha512-Wz4zuA6yo0Q4WbVEO61fvFin+6VTNjkBqHPhHCqq6dIoGdFSjUZ3BCKan1ei0axIAda7ZDP+eebe2vCr+eqcHg==",
       "dev": true,
       "requires": {
         "ethers": "^4.0.27",
@@ -17139,9 +17139,9 @@
       "dev": true
     },
     "pull-to-stream": {
-      "version": "0.1.0",
-      "resolved": "https://registry.npmjs.org/pull-to-stream/-/pull-to-stream-0.1.0.tgz",
-      "integrity": "sha512-LMvdE0JwT7XQZMFjc7JDl/G9gmoZ8Zo8e86SG4ZZUcjuwvod803KxpAK8WrmdxzHsMRK9DETlIzuA0tbEVv6jg==",
+      "version": "0.1.1",
+      "resolved": "https://registry.npmjs.org/pull-to-stream/-/pull-to-stream-0.1.1.tgz",
+      "integrity": "sha512-thZkMv6F9PILt9zdvpI2gxs19mkDrlixYKX6cOBxAW16i1NZH+yLAmF4r8QfJ69zuQh27e01JZP9y27tsH021w==",
       "dev": true,
       "requires": {
         "readable-stream": "^3.1.1"
diff --git a/package.json b/package.json
index 980bd03..bf43f95 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,7 @@
     "eslint-plugin-ember": "^5.2.0",
     "ethers": "^4.0.27",
     "kosmos-schemas": "^2.0.0",
-    "kredits-contracts": "^5.2.0",
+    "kredits-contracts": "^5.3.0",
     "loader.js": "^4.7.0",
     "qunit-dom": "^0.8.0",
     "tv4": "^1.3.0"
diff --git a/tests/unit/helpers/contribution-status.js b/tests/unit/helpers/contribution-status.js
new file mode 100644
index 0000000..785b56c
--- /dev/null
+++ b/tests/unit/helpers/contribution-status.js
@@ -0,0 +1,21 @@
+import { module, test } from 'qunit';
+import { setupTest } from 'ember-qunit';
+
+module('Unit | Helper | contribution-status', function (hooks) {
+  setupTest(hooks);
+
+  test('returns the appropriate status', function (assert) {
+    const contributionStatus = this.owner.factoryFor('helper:contribution-status').create();
+    const kredits = this.owner.lookup('service:kredits');
+
+    kredits.set('currentBlock', 23000);
+
+    const contributionUnconfirmed = { confirmedAt: 23001, vetoed: false };
+    const contributionConfirmed   = { confirmedAt: 21000, vetoed: false };
+    const contributionVetoed      = { confirmedAt: 23001, vetoed: true };
+
+    assert.eq(contributionStatus.compute([contributionUnconfirmed]), 'unconfirmed');
+    assert.eq(contributionStatus.compute([contributionConfirmed]), 'confirmed');
+    assert.eq(contributionStatus.compute([contributionVetoed]), 'vetoed');
+  });
+});
diff --git a/tests/unit/helpers/is-confirmed-contribution.js b/tests/unit/helpers/is-confirmed-contribution.js
new file mode 100644
index 0000000..3db7534
--- /dev/null
+++ b/tests/unit/helpers/is-confirmed-contribution.js
@@ -0,0 +1,21 @@
+import { module, test } from 'qunit';
+import { setupTest } from 'ember-qunit';
+
+module('Unit | Helper | contribution-status', function (hooks) {
+  setupTest(hooks);
+
+  test('returns the appropriate status', function (assert) {
+    const contributionStatus = this.owner.factoryFor('helper:contribution-status').create();
+    const kredits = this.owner.lookup('service:kredits');
+
+    kredits.set('currentBlock', 23000);
+
+    const contributionUnconfirmed = { confirmedAt: 23001, vetoed: false };
+    const contributionConfirmed   = { confirmedAt: 21000, vetoed: false };
+    const contributionVetoed      = { confirmedAt: 23001, vetoed: true };
+
+    assert.notOk(contributionStatus.compute([contributionUnconfirmed]), 'unconfirmed');
+    assert.notOk(contributionStatus.compute([contributionVetoed]), 'vetoed');
+    assert.ok(contributionStatus.compute([contributionConfirmed]), 'confirmed');
+  });
+});