add proposal app tests

apps/contribution/artifacts.js

@@ -0,0 +1,5 @@
+module.exports = {
+    Contribution: artifacts.require('Contribution.sol'),
+    getContributionContract: name => artifacts.require(name)
+}
+  

apps/contribution/test/contribution.js

@@ -8,7 +8,7 @@ const { assertRevert } = require('@aragon/test-helpers/assertThrow');
 
 const ZERO_ADDR = '0x0000000000000000000000000000000000000000';
 
-contract('Token app', (accounts) => {
+contract('Contribution app', (accounts) => {
     let kernelBase, aclBase, daoFactory, dao, acl, contribution, token;
   
     const root = accounts[0];