feat: manage long UID/GUID

Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine
+FROM alpine:latest
 
 RUN apk add --update-cache \
     rsync \

rsync.sh

@@ -11,7 +11,8 @@ echo "Preparation steps started."
 if [ "$RSYNC_UID" != "" ] && [ "$RSYNC_GID" != "" ]; then
     # UID and GID provided, create user
     echo "UID and GID provided: $RSYNC_UID and $RSYNC_GID. Creating the user"
-    adduser -D -u $RSYNC_UID -g $RSYNC_GID rsyncuser
+    echo "rsyncuser:x:$RSYNC_UID:$RSYNC_GID::/home/rsyncuser:/bin/sh" >> /etc/passwd
+    echo "users:x:$RSYNC_GID:rsyncuser" >> /etc/group
     RSYNC_USER=rsyncuser
 else
     # UID and GID not provided