adding queue name in the tutorial code example, because when you use the same queue name of the tutorial one, you get problems because the queue already exists

Author: gustavodemari

site/tutorials/tutorial-two-javascript.md

@@ -76,6 +76,7 @@ program will schedule tasks to our work queue, so let's name it
 `new_task.js`:
 
     :::javascript
+    var q = 'task_queue';
     var msg = process.argv.slice(2).join(' ') || "Hello World!";
 
     ch.assertQueue(q, {durable: true});