public HttpResponseMessage Unfollow(FollowUnfollowModel model)
 {
     db.PR_Unfollow(model.IdCard, model.IdFriend);
     return(Request.CreateResponse(HttpStatusCode.OK, "Ok"));
 }
        public IHttpActionResult IsFollowing(FollowUnfollowModel model)
        {
            var res = db.PR_GetFollowing(model.IdCard).Any(n => n.IdCard == model.IdFriend);

            return(Ok(res));
        }