public function check()
 {
     if (Authentication::getInstance()->isAuthenticated()) {
         $userModel = new UsersModel();
         $master = $userModel->getMasterKey(Authentication::getInstance()->getUserName());
         $master = $master[0]['master_key'];
         $response = new AJAXAnswer(true, $master);
     } else {
         $response = new AJAXAnswer(false, '');
     }
     $response->answer();
 }