in RoboFile.php [28:39]
function publishChanges() {
$user_name = exec('git config user.name');
$current_commit = exec('git rev-parse --verify HEAD');
return $this->taskGitStack()
->stopOnFail()
->dir('build')
->add('-A')
->commit("Robo build - $current_commit - $user_name")
->push('origin', 'gh-pages')
->run();
}