private ServiceResult AuthUser(AppUser user, string password)
        {
            if (user == null)
            {
                return(ServiceResultFactory.BadRequestResult(nameof(AuthenticateAsync), "Username was not found."));
            }

            var success = _passwordManager.VerifyPassword(password, user.PasswordHash, user.PasswordSalt);

            if (success == false)
            {
                return(ServiceResultFactory.BadRequestResult(nameof(AuthenticateAsync), "Password is wrong."));
            }

            return(ServiceResultFactory.SuccessResult(user));
        }