public async Task <IActionResult> Index()
        {
            var users = await _usersClient.GetAll();

            var model =
                users.Select(
                    u =>
                    new UserModel
            {
                UserId     = u.UserId,
                GivenName  = u.FirstName,
                FamilyName = u.LastName,
                Email      = u.Email
            }).ToList();

            return(View(model));
        }