You can go to burkes.github.io/emoji-picker to make installation easier.
No Browser extensions available. You can either run it manually, clicking the bookmark everytime you join a plug.dj room, or have it automatically load if you have an Userscript extension installed (i.e. Tampermonkey or Greasemonkey). Demonstration
Select the text below, and drag it to your bookmarks
javascript:(function(){$.getScript("//rawgit.com/Burkes/emoji-picker/master/dist/emoji-picker.min.js")})();
Or click to install it as an Userscript