Merge pull request #550 from osu-tournament-rating/feature/ping

Add `DiagnosticsController` with `ping` endpoint

API/Controllers/DiagnosticsController.cs

@@ -0,0 +1,20 @@
+using Asp.Versioning;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+
+namespace API.Controllers;
+
+[ApiController]
+[ApiVersion(1)]
+[Route("api/v{version:apiVersion}/[controller]")]
+public class DiagnosticsController : Controller
+{
+    /// <summary>
+    /// Allows clients to determine if the server is running  
+    /// </summary>
+    /// <response code="200>The server is running</response> 
+    [HttpGet("ping")]
+    [AllowAnonymous]
+    [ProducesResponseType(StatusCodes.Status200OK)]
+    public Task<IActionResult> PingAsync() => Task.FromResult<IActionResult>(Ok());
+}