Unbreak the chat sample

samples/ChatSample/Controllers/HomeController.cs

@@ -1,12 +1,14 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 
 namespace ChatSample.Controllers
 {
     public class HomeController : Controller
     {
+        [Authorize]
         public IActionResult Index()
         {
             return View();