public async Task <IActionResult> Create(SprintDetailViewModel model)
        {
            ViewData["Projects"]       = _projectService.GetAll();
            ViewData["SprintStatuses"] = _sprintService.GetAllSprintStatus();
            bool isExist = _sprintService.IsExistSprintNumber(model.Number);

            if (isExist)
            {
                ModelState.AddModelError("model.Number", "Số sprint này đã tồn tại. Bạn vui lòng chọn số sprint khác!");
            }
            if (!ModelState.IsValid)
            {
                return(View(model));
            }

            await _sprintService.Add(new Sprint
            {
                Number         = model.Number,
                Description    = model.Description,
                StartDate      = model.StartDate,
                EndDate        = model.EndDate,
                SprintStatusId = model.SprintStatusId,
                ProjectId      = model.ProjectId
            });

            return(RedirectToAction(nameof(Index)));
        }