/**
  * AJAX handler to update task statuses
  *
  * @param Request $request
  * @return \Illuminate\Http\JsonResponse
  */
 public function update(Request $request)
 {
     if ($request->ajax()) {
         $task = $request->input('task');
         $site = Site::find($request->input('site'));
         $site->tasks()->updateExistingPivot($task, ['completed' => !$site->tasks()->where('id', $task)->first()->pivot->completed]);
         return response()->json($site->id);
     }
 }