Properly handle systemd start/stop during Debian package install, closes #30

scripts/prerm.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+set -e
+
+# Stop systemd service
+if [ -d /run/systemd/system ] && [ "$1" = remove ]; then
+  echo "Stopping ntfy.service ..."
+  if [ -x /usr/bin/deb-systemd-invoke ]; then
+    deb-systemd-invoke stop 'ntfy.service' >/dev/null || true
+  else
+    systemctl stop ntfy >/dev/null 2>&1 || true
+  fi
+fi