public ActionResult Edit([Bind(Include = "GroupId,UserId,Title,StartDate,EndDate")] GroupTraining groupTraining)
 {
     if (ModelState.IsValid)
     {
         db.Entry(groupTraining).State = EntityState.Modified;
         db.SaveChanges();
         return(RedirectToAction("Index"));
     }
     return(View(groupTraining));
 }