Add GameController with SignalR functionality for joining games

API/API.csproj

@@ -11,4 +11,10 @@
     <PackageReference Include="Swashbuckle.AspNetCore" Version="7.2.0" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Folder Include="Models\" />
+    <Folder Include="Repository\" />
+    <Folder Include="Services\" />
+  </ItemGroup>
+
 </Project>

API/Controllers/GameController.cs

@@ -0,0 +1,16 @@
+using Microsoft.AspNetCore.SignalR;
+
+namespace API.Controllers;
+
+public class GameController : Hub
+{
+    public async Task JoinGame(string gameId, string playerName)
+    {
+        await Groups.AddToGroupAsync(Context.ConnectionId, gameId);
+        await Clients.Group(gameId).SendAsync("PlayerJoined", new
+        {
+            ConnectionId = Context.ConnectionId,
+            PlayerName = playerName
+        });
+    }
+}