public async Task <IActionResult> Register(RegisterViewModel user)
        {
            if (ModelState.IsValid)
            {
                if (user.Password != user.ConfirmPassword)
                {
                    ModelState.AddModelError("ConfirmPassword", "Password and ConfirmPassword must match.");
                    return(View(user));
                }
                Users _user = await db.Users.FirstOrDefaultAsync(u => u.Login == user.Login);

                if (_user == null)
                {
                    // добавляем пользователя в бд
                    db.Users.Add(new Users {
                        Login = user.Login, Password = EncryptHelper.Encrypt(user.Password)
                    });
                    await db.SaveChangesAsync();

                    await Authenticate(user.Login); // аутентификация

                    return(RedirectToAction("Index", "Transactions"));
                }
                else
                {
                    ModelState.AddModelError("Login", "Current user with such login is already exist.");
                }
            }
            return(View(user));
        }
 public async Task Save()
 {
     await _context.SaveChangesAsync();
 }