public ViewResult CreateCategory()
        {
            var viewModel = new AdminEditCategoryViewModel
                                {
                                    Category = new Category()
                                };

            return View("EditCategory", viewModel);
        }
        public ViewResult EditCategory(Guid id)
        {
            var viewModel = new AdminEditCategoryViewModel
                                {
                                    Category = _categoriesRepository.Get(id)
                                };

            return View(viewModel);
        }
        public ActionResult EditCategory(Category category)
        {
            if (ModelState.IsValid) {
                _categoriesRepository.SaveOrUpdate(category);

                TempData["message"] = string.Format("{0} has been saved", category.Name);

                return RedirectToAction("Categories");
            }

            var viewModel = new AdminEditCategoryViewModel
                                {
                                    Category = category
                                };

            return View(viewModel);
        }