// GET: Usuario/Create
        public ActionResult Create()
        {
            List <SelectListItem> item = context.listarRoles().ConvertAll(rol =>
            {
                return(new SelectListItem()
                {
                    Text = rol.NOMBRE,
                    Value = rol.ID_ROL.ToString()
                });
            });

            ViewBag.items = item;
            return(View());
        }