fixing dumb mistake ^^

Dockerfile

@@ -20,9 +20,10 @@ RUN apt-get update \
     && chmod +x papermc.sh \
     && chmod +x backup.sh \
     && chmod +x restore.sh
+RUN groupadd -r mcuser && adduser mcuser
 RUN chown -R ${user} /papermc
 RUN chown -R ${user} /backup
-RUN groupadd -r mcuser && adduser mcuser
+
 USER mcuser