/**
* Return all series and relation.
*
* /admin/series get
*
* @return Illuminate\Database\Eloquent\Collection|\Learner\Models\Series[]
*/
public function index()
{
$series = $this->series->findAllWithRelation();
$categories = $this->categories->listIdAndName();
return $this->responseJson(compact('series', 'categories'));
}