// Reference: http://lea.verou.me/2011/10/easily-keep-gh-pages-in-sync-with-master/
$ git add .
$ git status // to see what changes are going to be commited
$ git commit -m 'Some descriptive commit message'
$ git push origin trunk
$ git checkout gh-pages // go to the gh-pages branch
$ git rebase trunk // bring gh-pages up to date with trunk
$ git push origin gh-pages // commit the changes
$ git checkout trunk // return to the trunk branch