feat: Add [Authorize] to AdminController

Controllers/AdminController.cs

@@ -1,9 +1,11 @@
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
 using NoticeBoard.Data;
 
 namespace NoticeBoard.Controllers;
 
+[Authorize]
 public class AdminController : Controller
 {
     private readonly AppDbContext _db;