public async Task <IActionResult> Delete(int id, string returnUrl = "/")
        {
            var announcement = announcementService.GetAnnouncement(id);

            if (announcement == null)
            {
                return(NotFound());
            }
            var authorizationResult = await authorizationService.AuthorizeAsync(User, announcement, Operations.Delete);

            if (authorizationResult.Succeeded)
            {
                announcementService.DeleteAnnouncement(id);
                TempData["Toast"] = Toasts.AnnouncementDeleted;
                return(Redirect(returnUrl));
            }
            else
            {
                return(Forbid());
            }
        }