@Chris Oliver, Nice series tutorial. I really enjoy this series of tutorial.
If you have time and If you will convert this embeddable series with React JS then it would be nice. I like your tutorials and also I increase my skills through your tutorial.

I just notices a rails helper method for escaping the html on show.html.erb, :html_escape

example:

helper.send(:html_escape, 'is a > 0 & a < 10?')

It might be easier.

Wait, that might not work well.

skip_before_action :verify_authenticity_token is being used in comments controller - seems like a bad idea. how can we ensure csrf protection?

In case anyone else runs into this issue with Rails 6 and Webpacker, I needed to replace: sources_from_pack_manifest with sources_from_manifest_entries.