Fix errors and add commas,

Controllers/ExampleController.cs

@@ -2,10 +2,23 @@ using Microsoft.AspNetCore.Mvc;
 
 namespace TG_Bot_Template.Controllers
 {
+    /// <summary>
+    /// Example controller
+    /// </summary>
     [ApiController]
     [Route("[controller]")]
     public class ExampleController : ControllerBase
     {
-        
+        /// <summary>
+        /// Just example endpoing
+        /// </summary>
+        /// <returns></returns>
+        [HttpGet("ping")]
+        [Produces("application/json")]
+        [ProducesResponseType(200)]
+        public async Task<IActionResult> Pong()
+        {
+            return Ok("Pong!");
+        }
     }
 }