public async Task <IActionResult> CreateUpdateParticipant(ParticipantCreateUpdateViewModel viewmodel)
        {
            var answer = Answer.Error();

            if (viewmodel.Id.IsNotEmptyString())
            {
                answer = await Gateway.UpdateParticipant(viewmodel);
            }
            else
            {
                answer = await Gateway.CreateParticipant(viewmodel);
            }

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