public ActionResult UpdateCategory(Category category)
 {
     try
     {
         using (DatabaseQuery query = new DatabaseQuery())
         {
             if (ModelState.IsValid) //check of de modelstate goed is
             {
                 query.UpdateCategory(category);
                 return RedirectToAction("CategoryOverview");
             }
         }
     }
     catch (Exception e)
     {
         ViewBag.Error = "Er is iets fout gegaan met het updaten van de categorie: " + e;
         return RedirectToAction("ChangeCategory", category);
     }
     return RedirectToAction("category");
 }