public IHttpActionResult GetAccessToken(string username, string password)
        {
            var user = userManager.ValidateAndReturnUser(username, password);

            if (user != null && !user.IsLockedOut)
            {
                userManager.Lock(user.Id, false);
                var userId   = user.Id;
                var clientId = user.ClientId;
                var newToken = tokenGenerator.GetToken(userId);

                var accessTokenForClient = new AcccessTokenForClient(newToken, (int)clientId);

                return(Ok(accessTokenForClient));
            }
            else
            {
                return(Unauthorized());
            }
        }