public HttpResponseMessage Post(FacebookTokenModel model)
        {
            string token;

            try
            {
                token = _facebookService.ExtendToken(model.Token);
            }
            catch (BadRequestException e)
            {
                ModelState.AddModelError("Token", e.Message);
                return(Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState));
            }

            var response = new FacebookToken {
                Token = token
            };

            return(Request.CreateResponse(HttpStatusCode.OK, response));
        }