Write your documentation in Markdown inside your repository, versioned with your code. Couscous will turn those Markdown files to HTML.
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.
couscous deploy will publish your website on the gh-pages Git branch. GitHub will automatically put it online and host it for you.
Your website is online, just sit back and relax.
Find more static site generators.