This container is pre-configured according to the
GitHub Pages use of Jekyll.
It serves up the generated content on port 4000 and the site is generated from
/site volume. You can either bring your own site content or
let it generate some VERY simple content along with the standard Jekyll directory
A typical way to run this:
docker run -it -p 4000:4000 -v $(pwd)/site:/site itzg/jekyll-github-pages
where either it will load your content or initialize the content under
site in your current working directory.