jekyll-gist-it-tag is a Jekyll plugin to use the gist-it AppEngine app to embed any file from a github repository like a gist.
Add jekyll-gist-it-tag.rb to the _plugins directory of your Jekyll site.
{% gist_it *any_GitHub_file_url* %}
{% gist_it https://github.com/robinhowlett/jekyll-gist-it-tag/blob/master/jekyll-gist-it-tag.rb %}