/**
  * Display a listing of the resource.
  *
  * @return Response
  */
 public function index()
 {
     if (Input::has('Modality')) {
         $generators = PowerGenerator::where('Modality_Id', '=', Input::get('Modality'))->get();
     } else {
         $generators = PowerGenerator::all();
     }
     if (Request::ajax()) {
         return Response::json($generators->lists('Name', 'Id'));
     }
     return View::make('power_generators.index', compact('generators'));
 }