Build code-runner app

[kallewesterling]

From @szweibel on July 1:

Look at Sphinx Thebelab, created for Sphinx
https://twitter.com/choldgraf/status/1278391533390053376?s=20

[kallewesterling]

From @lmrhody on July 14:

Leaving this here for us to discuss: https://repl.it/
The Commons team has just added shortcode solution for embedding it into a Commons site to use.
There’s discussion about how we might embed a jupyter notebook.
Basically, if we were to embed this into our curriculum site, we could run code in the browser.