Update extension.js

This will auto-disable the DJ cycle if the wait list reaches 21 people and enable it when it reaches 14, theoretically... I haven't been able to test it because I don't have a room with more than 20 people in it, enabling it works though! (I don't have a room with even 1 person other than me in it :p)
Merge pull request #5 from Gamefreak0/patch-5

Update extension.js