Adds yank button to the web UI (initial)

Author: thiagoarrais

app/controllers/crate/version.js

@@ -152,4 +152,8 @@ export default Controller.extend({
   loadDocsBuilds: task(function* () {
     return yield ajax(`https://docs.rs/crate/${this.crate.name}/${this.currentVersion.num}/builds.json`);
   }),
+
+  yankVersionTask: task(function* (version) {
+    return version.yank.perform();
+  }),
 });

app/models/version.js

@@ -60,4 +60,14 @@ export default class Version extends Model {
     }
   }).keepLatest())
   loadReadmeTask;
+
+  @(task(function* () {
+    let response = yield fetch(`/api/v1/crates/${this.crate.id}/${this.num}/yank`, { method: 'DELETE' });
+    if (!response.ok) {
+      throw new Error(`Yank request for ${this.crateName} v${this.num} failed`);
+    }
+
+    return yield response.text();
+  }).keepLatest())
+  yank;
 }

app/templates/crate/version.hbs

@@ -171,6 +171,9 @@
                 {{#if version.yanked}}
                   <span local-class='yanked'>yanked</span>
                 {{/if}}
+                {{#if isOwner}}
+                  <button type="button" local-class="remove-button" {{on "click" (perform this.yankVersionTask version)}}>Yank</button>
+                {{/if}}
               </li>
             {{/each}}
           </ul>