public function modify()
 {
     $uid = $this->authorizer->getResourceOwnerId();
     $this->prepareModify($uid);
     $user = User::find($uid);
     $allowedFields = ['avatar_url', 'display_name', 'gender', 'email', 'company'];
     array_walk($allowedFields, function ($item) use($user, $uid) {
         $v = Request::input($item);
         if ($v && $item !== 'avatar_url') {
             $user->{$item} = $v;
         }
         if (Request::hasFile('avatar_url')) {
             $user->avatar_url = MultiplexController::uploadAvatar($uid);
         }
     });
     $user->save();
     return $this->dbRepository('mongodb', 'user')->find($uid);
 }