During the weekly developer hangout, @bpaniagua and I talk about this, and we suggest to setup a cron job on the server that is currently serving “slicer.org” ?
A cron job like this one (running every minutes) should do the work:
SITE_DIR=/path/to/slicer.org
if [[ ! -d $SITE_DIR ]]; then
git clone https://github.com/Slicer/slicer.org $SITE_DIR
fi
cd $SITE_DIR
git fetch origin
git reset --hard origin/gh-pages