mention the name of the uid/gid

Author: ibotty

Dockerfile.rootless

@@ -56,7 +56,7 @@ COPY docker/rootless /
 COPY --from=build-env --chown=root:root /go/src/code.gitea.io/gitea/gitea /usr/local/bin/gitea
 COPY --from=build-env --chown=root:root /go/src/code.gitea.io/gitea/environment-to-ini /usr/local/bin/environment-to-ini
 
-USER 1000:1000
+USER 1000:1000 # git:git
 ENV GITEA_WORK_DIR /var/lib/gitea
 ENV GITEA_CUSTOM /var/lib/gitea/custom
 ENV GITEA_TEMP /tmp/gitea