====== Update letsencrypt certificates for wiki and ejabber ======

  * Stop apache web server
  * Run 

  sudo certbot --authenticator standalone --installer apache --pre-hook "service apache2 stop" --post-hook "service apache2 start"  renew

  * Restart apache
  * Stop ejabberd
  * Run script:

  /etc/ejabber/update-cert.sh

  * Start ejabberd
  * That's it!