public ActionResult Add(Product productModel)
 {
     if (ModelState.IsValid)
     {
         DocumentSession.Store(productModel);
         return RedirectToAction("Index");
     }
     return View(productModel);
 }
 public ActionResult Edit(Product productModel)
 {
     if (ModelState.IsValid)
     {
         var product = DocumentSession.Load<Product>(productModel.Id);
         product.Title = productModel.Title;
         product.Description = productModel.Description;
         product.Price = productModel.Price;
         product.Featured = productModel.Featured;
         return RedirectToAction("Index");
     }
     return View("Add", productModel);
 }