Shameless self-promotion:

"Why can't I copy a URL to my editor to enable real-time collaboration with someone else?"

That's one of the things we (Scrimba) are trying to enable dev teams to do seamlessly these days: https://www.youtube.com/watch?v=Rsorl3-TjdY

Instructions on how to try our beta can be found here: https://scrimba.com:9000/@welcome