public async Task <IActionResult> Delete(int?id)
        {
            if (id != null)
            {
                ForumCategoryModel model = await _db.ForumCategories
                                           .Include(t => (t.Topics as TopicModel).Replies)
                                           .ThenInclude(t => t.Pictures)
                                           .Include(t => (t.Topics as TopicModel).Pictures)
                                           .Include(t => t.Topics)
                                           .FirstOrDefaultAsync(p => p.Id == id);

                if (model != null)
                {
                    _db.DeleteForumCategory(model);
                    await _db.SaveChangesAsync();

                    return(RedirectToAction("Index"));
                }
            }
            return(NotFound());
        }