Fix admin route access and backend configuration

- Added /admin redirect to login page in nginx config
- Fixed backend server.js route ordering for proper admin handling
- Updated authentication middleware and routes
- Added user management routes
- Configured PostgreSQL integration
- Updated environment configuration

Sky_Art_shop/Controllers/AdminSettingsController.cs

@@ -0,0 +1,54 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Authorization;
+using SkyArtShop.Models;
+using SkyArtShop.Services;
+
+namespace SkyArtShop.Controllers
+{
+    [Route("admin/settings")]
+    [Authorize(Roles="Admin")]
+    public class AdminSettingsController : Controller
+    {
+        private readonly MongoDBService _mongoService;
+        private readonly string _settingsCollection = "SiteSettings";
+
+        public AdminSettingsController(MongoDBService mongoService)
+        {
+            _mongoService = mongoService;
+        }
+
+        [HttpGet("")]
+        public async Task<IActionResult> Index()
+        {
+            var settingsList = await _mongoService.GetAllAsync<SiteSettings>(_settingsCollection);
+            var settings = settingsList.FirstOrDefault();
+            if (settings == null)
+            {
+                settings = new SiteSettings();
+                await _mongoService.InsertAsync(_settingsCollection, settings);
+            }
+            return View(settings);
+        }
+
+        [HttpPost("update")]
+        public async Task<IActionResult> Update(SiteSettings settings)
+        {
+            if (!ModelState.IsValid)
+            {
+                return View("Index", settings);
+            }
+
+            settings.UpdatedAt = DateTime.UtcNow;
+            if (!string.IsNullOrEmpty(settings.Id))
+            {
+                await _mongoService.UpdateAsync(_settingsCollection, settings.Id, settings);
+            }
+            else
+            {
+                await _mongoService.InsertAsync(_settingsCollection, settings);
+            }
+            TempData["SuccessMessage"] = "Site settings updated successfully!";
+            return RedirectToAction("Index");
+        }
+    }
+}