Add proposal form

Closes #6

Form can be prefilled using query params on the route. The params are
`recipient`, `amount`, `url` and `ipfsHash`.

tests/integration/components/add-proposal/component-test.js

@@ -0,0 +1,16 @@
+import { moduleForComponent, test } from 'ember-qunit';
+import hbs from 'htmlbars-inline-precompile';
+
+moduleForComponent('add-proposal', 'Integration | Component | add proposal', {
+  integration: true
+});
+
+test('it renders', function(assert) {
+
+  // Set any properties with this.set('myProperty', 'value');
+  // Handle any actions with this.on('myAction', function(val) { ... });
+
+  this.render(hbs`{{add-proposal}}`);
+
+  assert.equal(this.$('.actions a').text().trim(), 'Back');
+});