/**
  *
  * create a new album
  * @param Request $request
  * @return \Illuminate\Http\JsonResponse
  */
 public function add(Request $request)
 {
     try {
         $this->validate($request, Album::$rules);
         $input = $request->all();
         $album = new Album($input);
         $artists = Artist::whereIn('id', $input['author'])->get();
         $album->save();
         $album->artist()->saveMany($artists);
         return response()->json(['status' => 'success']);
     } catch (ValidationException $e) {
         return response()->json(['status' => 'validation_error', 'messages' => $e->validator->errors()]);
     } catch (\Exception $e) {
         return response()->json(['status' => 'server_error', 'message' => $e->getMessage()]);
     }
 }