Fix "Unsupported rule: jsDoc" when linting

no issue
- add missing jscs-jsdoc dependency and specify plugin in .jscsrc
- fix linting issue in user-test.js

ghost/admin/tests/unit/models/user-test.js

@@ -4,7 +4,7 @@ import {
     it
 } from 'ember-mocha';
 
-const { run } = Ember;
+const {run} = Ember;
 
 describeModel(
     'user',