Couscous
Step 1
Write your documentation in Markdown inside your repository, versioned with your code. Couscous will turn those Markdown files to HTML.
Step 2
couscous preview
will render the website on your machine. Tweak the default template, fix some typos and the changes will be reflected in real time.
Step 3
couscous deploy will publish your website on the gh-pages Git branch. GitHub will automatically put it online and host it for you.
Step 4
Your website is online, just sit back and relax.