public ActionResult Activate_DeactivateSemester(Semester input)
        {
            Semester change = (from m in db.Semesters
                               where m.Id == input.Id
                               select m).First();

            change.Active = input.Active;

            db.SaveChanges();

            return RedirectToAction("Index");
        }
        public ActionResult CreateSemester(Semester input)
        {
            if (input.Active == null)
                input.Active = false;

            Semester check = (from m in db.Semesters
                              where m.Name == input.Name &&
                                m.Year == input.Year
                              select m).FirstOrDefault();
            if (check == null)
                db.Semesters.Add(input);

            else
            {
                ViewBag.error = "Semester already exists.";
                return View();
            }

            db.SaveChanges();

            return RedirectToAction("Index");
        }