public int LogOn(string user, string pw)
        {
            var tmp = db.Users.Where(u => u.Active);
            if (!String.IsNullOrEmpty(user) && !String.IsNullOrEmpty(pw))
            {
                tmp = tmp.Where(u => u.UserName == user && u.Password == pw);
                return tmp.Single(u => u.Permission);
            }

            return 0;
        }