Add in the middle ware and Fallbackcontroller.

CarParkValidationAPI/Controllers/FallbackController.cs

@@ -0,0 +1,18 @@
+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace CarParkValidationAPI.Controllers
+{
+    public class FallbackController : Controller
+    {
+        public IActionResult Index()
+        {
+            return PhysicalFile(Path.Combine(Directory.GetCurrentDirectory(),
+                "wwwroot", "index.html"), "text/HTML");
+        }
+    }
+}