Creates a gh-pages branch based on a gh-pages directory, and serves its contents as a <username>.github.io website

GitHub pages branch

# First time
mkdir gh-pages
touch gh-pages/index.html
git add gh-pages
git commit -m "First commit of GitHub Pages branch"
git push origin master

# Subsequent times
# Edit, save, commit, push files inside gh-pages directory
git subtree push --prefix gh-pages origin gh-pages