public ActionResult Create(Subsystem subsystem)
        {
            if (ModelState.IsValid)
            {
                db.Subsystems.Add(subsystem);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

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