Updates to user/group determination after recent changes to v2 branch

docker/rootfs/etc/s6-overlay/s6-rc.d/prepare/10-npmuser.sh

@@ -0,0 +1,20 @@
+#!/command/with-contenv bash
+# shellcheck shell=bash
+
+set -e
+
+log_info 'Configuring npmuser ...'
+
+if id -u npmuser; then
+	# user already exists
+	usermod -u "$PUID" npmuser || exit 1
+else
+	# Add npmuser user
+	useradd -o -u "$PUID" -U -d /tmp/npmuserhome -s /bin/false npmuser || exit 1
+fi
+
+usermod -G "$PGID" npmuser || exit 1
+groupmod -o -g "$PGID" npmuser || exit 1
+# Home for npmuser
+mkdir -p /tmp/npmuserhome
+chown -R "$PUID:$PGID" /tmp/npmuserhome