public async Task<IActionResult> Create(ToDo todo)
 {
     var currentUser = await _userManager.FindByIdAsync(User.GetUserId());
     try
     {
         todo.User = currentUser;
         _db.ToDoes.Add(todo);
         _db.SaveChanges();
         return RedirectToAction("Index");
     }
     catch(Exception ex)
     {
         System.Diagnostics.Debug.Write(ex);
         return View(todo);
     }
 }
 public IActionResult Edit (ToDo todo)
 {
     _db.Entry(todo).State = EntityState.Modified;
     _db.SaveChanges();
     return RedirectToAction("Index");
 }