private void UpdateThread()
        {
            while (true)
            {
                var announcements = BulletinBoardService.GetAnnouncements();
                try
                {
                    Dispatcher.Invoke(() =>
                    {
                        foreach (var announcement in announcements)
                        {
                            if (!Announcements.Contains(announcement))
                            {
                                AddAnnouncement(announcement);
                            }
                        }
                    });
                }
                catch (TaskCanceledException)
                {
                    break;
                }

                Thread.Sleep(1000);
            }
        }