public NotificationManager(IUserNotificationRepository userNotificationRepository
     ,IEmailProvider emailProvider
     ,IBoardUserShareRepository boardUserShareRepository
     ,IUserManager userManager)
 {
     _userNotificationRepository = userNotificationRepository;
     _userNotificationRepository.EnsureExist();
     _emailProvider = emailProvider;
     _boardUserShareRepository = boardUserShareRepository;
     _userManager = userManager;
 }