public async Task <IActionResult> UpdateAnnouncement(Guid announcementId, [FromBody] ModifyAnnouncementRequest request)
 => await Mediator
 .Send(new UpdateCommand <AnnouncementResponse>(request, announcementId))
 .ToOkResult();
 public async Task <IActionResult> CreateAnnouncement([FromBody] ModifyAnnouncementRequest request)
 => await Mediator
 .Send(new CreateCommand <AnnouncementResponse>(request))
 .ToCreatedAtResult <Response <AnnouncementResponse>, AnnouncementResponse, GetAnnouncementRoute>();