do-gh-pages

#!/bin/sh

PARENT_SHA=$(git show-ref -s refs/heads/gh-pages)
DOC_SHA=$(git ls-tree -d HEAD doc | awk '{print $3}')
NEW_COMMIT=$(echo "Auto-update docs." | git commit-tree $DOC_SHA -p $PARENT_SHA)
git update-ref refs/heads/gh-pages $NEW_COMMIT