PHP webhook to pull and Gulp build automatically after push

webhook.php

<?php

if ( isset($_POST['payload']) && $_POST['payload'] ) {
  echo shell_exec('cd /var/www/mydrupal/ && sudo -u myuser git pull');
  echo shell_exec('cd /var/www/mydrupal/sites/all/themes/mytheme/ && sudo -u myuser node ./node_modules/gulp/bin/gulp.js mygulptask');
  // Adding the drush will cause the delivery being displayed as unsuccessful. Means GitHub doesn't wait so long. The command will run nevertheless.
  echo shell_exec('cd /var/www/mydrupal/ && sudo -u myuser drush @sites cc all -y');
}

// Should return www-data
echo shell_exec('whoami');
// Should return myuser
echo shell_exec('sudo -u myuser whoami');

?>

/etc/sudoers:

www-data ALL = (myuser) NOPASSWD: /usr/bin/git
www-data ALL = (myuser) NOPASSWD: /usr/bin/node
www-data ALL = (myuser) NOPASSWD: /usr/bin/drush
www-data ALL = (myuser) NOPASSWD: /usr/bin/whoami

Thanks man! this works!