public async Task <IHttpActionResult> AddExternalLogin(AddExternalLoginBindingModel model)
        {
            if (!ModelState.IsValid)
            {
                return(BadRequest(ModelState));
            }

            var result = await _authorizationService.AddExternalLogin(User, model.ExternalAccessToken);

            if (result is BadRequestResult)
            {
                return(BadRequest((result as BadRequestResult).Message));
            }

            if (result is ErrorResult)
            {
                var error = result as ErrorResult;
                if (!error.Succeeded)
                {
                    return(GetErrorResult(error));
                }
            }

            return(Ok());
        }