I think it would be better to use the HTTPS URL instead of SSH by default. It is more compatible with firewalls, CI servers, deployment, etc.

On the Bundler 2.0 branch, the GitHub shortcut has switched to using HTTPS, too. We couldn't do that in 1.x because it causes the lock file to change (which breaks backward compatibility) but for a new source I think we might as well go that way from the start.