public ActionResult Edit(GroupEditViewModel model)
 {
     if (ModelState.IsValid)
     {
         try
         {
             Group group = _groupManager.GetGroupById(new ObjectId(model.Id));
             group.Name        = model.Name;
             group.Description = model.Description;
             _groupManager.UpdateGroup(group);
             return(RedirectToAction("Index", "Group", new { id = model.Id }));
         }
         catch (Exception)
         {
             return(View(model));
         }
     }
     return(View(model));
 }