public ActionResult Add(Problem newProblem, FormCollection form)
        {
            ProblemModel pm = new ProblemModel();

            if (ModelState.IsValid)
            {
                newProblem.AuthorID = (int)Session["UserID"];
                newProblem.Points   = 1;
                newProblem.IsSolved = false;
                var AllStrings = form["checkboxTag"].Split(',');
                foreach (string item in AllStrings)
                {
                    int value = int.Parse(item);
                    var tag   = _tagRepo.GetTagById(value);
                    newProblem.Tags.Add(tag);
                }
                pm.AddProblem(newProblem);
                return(RedirectToAction("Index"));
            }
            else
            {
                return(RedirectToAction("Index"));
            }
        }