post_install() {
  getent passwd signal > /dev/null || useradd -d /var/lib/signal-web-gateway signal > /dev/null
  getent group signal > /dev/null || groupadd -r signal > /dev/null
  chown -R signal:signal /var/lib/signal-web-gateway
}
 
post_remove() {
   userdel -rf signal
   groupdel signal
}