Added support for ruby runtime

[anandology]

Right now only two runtimes are supported: python and python-canvas.

Extend LiveCode to support ruby runtime.

[nikochiko]

@anandology I would like to pick this up.

I tried getting started with setting up falcon on codespaces, but only the "python" tab is working properly for me, and the static files beyond livecode.js and livecode-demo.js are throwing a 404. I'll try running this locally as well and see if that issue still persists.