public async Task <IActionResult> Delete(int?id)
        {
            var deleteStudent = _studentsRepository.GetSingle(s => s.ID == id);

            if (deleteStudent == null)
            {
                return(new NotFoundResult());
            }
            else
            {
                IEnumerable <Enrollment> enrollments = _enrollmentRepository.FindBy(e => e.StudentID == id);

                foreach (var enrollment in enrollments)
                {
                    _enrollmentRepository.Delete(enrollment);
                }

                _studentsRepository.Delete(deleteStudent);

                await _studentsRepository.CommitAsync();

                return(new NoContentResult());
            }
        }