Fix `store.push` deprecations in user model test
Fix `store.push` deprecations in user model test

no issue
- `store.push` now accepts a single argument that is a JSON API compliant object (http://emberjs.com/blog/2015/06/18/ember-data-1-13-released.html#toc_internal-format-change-to-json-api)

TryGhost/Ghost,TryGhost/Ghost,TryGhost/Ghost