public ActionResult CreateCategory(Category category)
        {
            var rep = new CategoryRepository();
            rep.Create(category);

            return RedirectToAction("Group");
        }
 partial void DeleteCategory(Category instance);
 partial void UpdateCategory(Category instance);
 partial void InsertCategory(Category instance);
		private void detach_Category(Category entity)
		{
			this.SendPropertyChanging();
			entity.Group = null;
		}
		private void attach_Category(Category entity)
		{
			this.SendPropertyChanging();
			entity.Group = this;
		}