public ActionResult AddGroup(GroupViewModel groupViewModel)
        {
            try
            {
                if (ModelState.IsValid)
                {
                    GroupDTO groupDto = _mapper.Map <GroupViewModel, GroupDTO>(groupViewModel);
                    var      groupId  = _timeTableService.AddGroup(groupDto);
                    return(Json(new { success = true, id = groupId }));
                }
            }
            catch (ValidationException ex)
            {
                ViewBag.Error = ex.Message;
                return(Json(new { success = false, errorMessage = ex.Message }));
            }

            return(PartialView("_AddGroupFormPartial", groupViewModel));
        }