public IActionResult Create(SeminarCreateViewModel model, string returnUrl = null)
        {
            ViewData["ReturnUrl"] = returnUrl;
            if (ModelState.IsValid)
            {
                Seminar seminar = new Seminar
                {
                    Id          = new System.Guid(),
                    Title       = model.Title,
                    Description = model.Description,
                    Content     = model.Content
                };
                _seminarService.CreateSeminar(seminar);


                // return View(model);
            }

            return(View(model));
        }