public IActionResult AddStudentToGroup(Guid id)
        {
            var addStudentToGroup = new AddStudentToGroupViewModel {
                GroupId = id
            };

            return(View(addStudentToGroup));
        }
        public async Task <IActionResult> AddStudentToGroup(AddStudentToGroupViewModel addStudentToGroupViewModel)
        {
            var students = await _usersRepository.GetStudentsByNamePrefixAsync(addStudentToGroupViewModel.StudentName);


            if (!ModelState.IsValid)
            {
                return(View(addStudentToGroupViewModel));
            }



            var inserted = await _groupsRepository
                           .InsertStudentAsync(addStudentToGroupViewModel.GroupId, students[0].Id);

            if (!inserted)
            {
                return(NotFound());
            }

            return(RedirectToAction(nameof(AddStudentToGroup), new { id = addStudentToGroupViewModel.GroupId }));
        }