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

Controllers/AdminSettingsController.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using SkyArtShop.Models;
+using SkyArtShop.Services;
+
+namespace SkyArtShop.Controllers;
+
+[Route("admin/settings")]
+[Authorize(Roles = "Admin,MasterAdmin")]
+public class AdminSettingsController : Controller
+{
+	private readonly PostgreSQLService _pgService;
+
+	private readonly string _settingsCollection = "SiteSettings";
+
+	public AdminSettingsController(PostgreSQLService pgService)
+	{
+		_pgService = pgService;
+	}
+
+	[HttpGet("")]
+	public async Task<IActionResult> Index()
+	{
+		SiteSettings settings = (await _pgService.GetAllAsync<SiteSettings>(_settingsCollection)).FirstOrDefault();
+		if (settings == null)
+		{
+			settings = new SiteSettings();
+			await _pgService.InsertAsync(_settingsCollection, settings);
+		}
+		return View(settings);
+	}
+
+	[HttpPost("update")]
+	public async Task<IActionResult> Update(SiteSettings settings)
+	{
+		if (!base.ModelState.IsValid)
+		{
+			return View("Index", settings);
+		}
+		settings.UpdatedAt = DateTime.UtcNow;
+		if (string.IsNullOrEmpty(settings.Id))
+		{
+			await _pgService.InsertAsync(_settingsCollection, settings);
+		}
+		else
+		{
+			await _pgService.UpdateAsync(_settingsCollection, settings.Id, settings);
+		}
+		base.TempData["SuccessMessage"] = "Site settings updated successfully!";
+		return RedirectToAction("Index");
+	}
+}