Add extension https://github.com/riknoll/arcade-dj

Fixes #146

Author: UnsignedArduino

content/extensions/070-riknoll---arcade-dj.md

@@ -0,0 +1,15 @@
+---
+repo: "https://github.com/riknoll/arcade-dj"
+links:
+  - title: Forum post
+    url: >-
+      https://forum.makecode.com/t/so-what-happened-to-the-dj-extension/29209/5?u=unsignedarduino
+  - title: Demo
+    url: "https://arcade.makecode.com/S60062-11234-81819-24053"
+betaStatus:
+  inBeta: true
+  since: "July 10, 2024"
+  reason: '"expect bugs and APIs might change." -@riknoll'
+---
+
+Looping and tracking the playing of songs in MakeCode Arcade is made easy with this extension! This adds a `DJ Arcade` category to the toolbox.