Replace apk tor user with manually generated user

Replace apk tor user with generated toranan user and group due to userns=auto GID 65533 mapping incompatibility. UID 100 is used to match original tor UID while GID 101 is used to avoid existing group.

Dockerfile

@@ -3,12 +3,15 @@ FROM alpine:edge
 RUN apk add --no-cache curl tor && rm -rf /var/cache/apk/* && \
     sed "1s/^/SocksPort 0.0.0.0:9050\n/" /etc/tor/torrc.sample > /etc/tor/torrc
 
+RUN sed -i '/tor:x:/d' /etc/passwd && sed -i 's/65533:tor/65533:/' /etc/group && \
+    addgroup -g 101 -S toranon && adduser -S -D -H -u 100 -s /sbin/nologin -G toranon -g toranon toranon
+
 EXPOSE 9050 9051
 
 HEALTHCHECK --interval=300s --timeout=15s --start-period=60s --start-interval=10s \
     CMD curl -x socks5h://127.0.0.1:9050 'https://check.torproject.org/api/ip' | grep -qm1 -E '"IsTor"\s*:\s*true'
 
 VOLUME ["/var/lib/tor"]
 
-USER tor
+USER toranon
 CMD ["tor"]