//Partial index that returns list of classes
        public ActionResult partIndex(FormCollection collection)
        {
            var sem = collection["sem_list"] ?? "";

                var viewModel = new ClassManagerIndexViewModel
                {
                    Semesters = db.Semesters.ToList(),
                    Classes = db.Classes.Where(c => sem == "" || c.semster_id == sem).ToList()
                };

            return PartialView(viewModel);
        }
        //Index of Class Manager
        public ActionResult Index()
        {
            var viewModel = new ClassManagerIndexViewModel
            {
                Semesters = db.Semesters.ToList(),
                Classes = db.Classes.ToList()
            };

            return View(viewModel);
        }