public ActionResult Create(Unit unit)
        {
            if (ModelState.IsValid)
            {
                db.Units.Add(unit);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(unit);
        }
        public ActionResult Edit(Unit unit)
        {
            if (ModelState.IsValid)
            {
                db.Entry(unit).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(unit);
        }