public function manageAction()
 {
     if ($this->authorizationService->getIdentity() === null) {
         throw new UnauthorizedException();
     }
     $user = $this->authorizationService->getIdentity();
     $subscriptions = $this->subscriptionManager->findSubscriptionsByUser($user);
     $view = new ViewModel(['subscriptions' => $subscriptions]);
     $view->setTemplate('notification/subscription/manage');
     return $view;
 }