app: Migrate versions.length to num_versions

Author: eth3lbert

app/components/crate-header.hbs

@@ -54,7 +54,7 @@
   </nav.Tab>
 
   <nav.Tab @link={{link "crate.versions" @crate}} data-test-versions-tab>
-    {{pluralize @crate.versions.length "Version"}}
+    {{pluralize @crate.num_versions "Version"}}
   </nav.Tab>
 
   <nav.Tab

app/models/crate.js

@@ -18,6 +18,7 @@ export default class Crate extends Model {
    * @type {string | null}
    */
   @attr default_version;
+  @attr num_versions;
   @attr yanked;
   @attr max_version;
   @attr max_stable_version;

app/templates/crate/versions.hbs

@@ -2,7 +2,7 @@
 
 <div local-class="results-meta">
   <span local-class="page-description" data-test-page-description>
-    All <strong>{{ this.model.versions.length }}</strong>
+    All <strong>{{ this.model.num_versions }}</strong>
     versions of <strong>{{ this.model.name }}</strong> since
     {{date-format this.model.created_at 'PPP'}}
   </span>