post_upgrade() {
  # hooks are ran *after* this function, so we have to call
  # systemd-sysusers manually to make sure the ordersprinter user exists
  systemd-sysusers
  mkdir -p /var/lib/ordersprinter
  chown -R ordersprinter:ordersprinter /var/lib/ordersprinter
  chown -R ordersprinter:ordersprinter /opt/ordersprinter/webapp
  chmod +x /usr/bin/ordersprinter
}