Added default route to swagger page

AdventOfCode/Controllers/HomeController.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace AdventOfCode.Controllers
+{
+    [ApiController]
+    [ApiExplorerSettings(IgnoreApi = true)]
+    public class HomeController : ControllerBase
+    {
+        [Route("")]
+        [HttpGet]
+        public IActionResult Index()
+        {
+            return Redirect("/swagger/Index.html");
+        }
+    }
+}