public ActionResult AddRoom(Room input)
        {
            Room check = (from m in db.Rooms
                          where m.BuildingID == input.BuildingID &&
                            m.Name == input.Name
                          select m).FirstOrDefault();

            if (check == null)
            {
                db.Rooms.Add(input);
                db.SaveChanges();
            }

            else
            {
                ViewBag.error = "Room already exists in this building.";
                return View();
            }

            return RedirectToAction("Index");
        }
        public ActionResult AddRoom(int id)
        {
            Building building = (from m in db.Buildings
                                 where m.Id == id
                                 select m).First();

            Room newRoom = new Room();
            newRoom.BuildingID = building.Id;

            return View(newRoom);
        }