add code hub test

BinaryDad.Coding/Hubs/CodeHub.cs

@@ -0,0 +1,16 @@
+using Microsoft.AspNetCore.SignalR;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace BinaryDad.Coding.Hubs
+{
+    public class CodeHub : Hub
+    {
+        public async Task SendMessage(string user, string message)
+        {
+            await Clients.All.SendAsync("ReceiveMessage", user, message);
+        }
+    }
+}