public bool Create(User instance)
        {
            if (instance.Id == 0)
            {
                Db.Users.Add(instance);
                Db.SaveChanges();

                return true;
            }

            return false;
        }
 public void Init(string login, IRepository repository)
 {
     if (!string.IsNullOrEmpty(login))
         User = repository.GetUser(login);
 }