add preinstall script for deb package

contrib/navidrome-uploader.service

@@ -20,7 +20,7 @@ AmbientCapabilities=
 ProtectSystem=strict
 ProtectHome=yes
 PrivateTmp=yes
-ReadWritePaths=/opt/navidrome-uploader
+ReadWritePaths=/opt/uploader
 InaccessiblePaths=/boot /mnt /media
 
 PrivateDevices=yes

release/preinstall.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+if ! getent passwd navidrome-uploader > /dev/null 2>&1; then
+    printf "Creating navidrome-uploader user\n"
+    useradd --system --shell /usr/sbin/nologin --user-group navidrome-uploader
+fi