public IActionResult CreateUpdateEvent(EventCreateUpdateViewModel viewmodel)
        {
            var answer = Answer.Error();

            if (viewmodel.Id.IsNotEmptyString())
            {
                answer = Gateway.UpdateEvent(viewmodel);
            }
            else
            {
                answer = Gateway.CreateEvent(viewmodel);
            }

            if (answer.AnswerType == AnswerType.Success)
            {
                return(RedirectToAction("Manage"));
            }
            else
            {
                return(View("CreateUpdateEvent", viewmodel));
            }
        }