The verbose option dumps a progress percentage to `STDERR`. I'm piping `STDOUT` to `/dev/null` in my backup cron job but I'd like to keep `STDERR` in case something goes wrong. However because the progress gets dumped to `STDERR` by gzip it means it will always look like something went _wrong_.
references #2308
```
I have also confirmed the base-image has support for the rsyncable option
root@whitebox:~# docker run debian:stretch-slim gzip --help | grep rsyncable
--rsyncable Make rsync-friendly archive
```
[Docker API] Create pipe to pass Rspamd UI worker password
[Dovecot] Pull Spamassassin ruleset to be read by Rspamd (MANY THANKS to Peer Heinlein!)
[Dovecot] Garbage collector for deleted maildirs (set keep time via MAILDIR_GC_TIME which defaults to 1440 minutes)
[Web] Flush memcached after mailbox item changes, fixes#1808
[Web] Fix duplicate IDs, fixes#1792
[Compose] Use SQL sockets
[PHP-FPM] Update APCu and Redis libs
[Dovecot] Encrypt maildir with global key pair in crypt-vol-1 (BACKUP!), also fixes#1791
[Web] Fix deletion of spam aliases
[Helper] Add "crypt" to backup script
[Helper] Override file for external SQL socket (not supported!)
[Compose] New images for Rspamd, PHP-FPM, SOGo, Dovecot, Docker API, Watchdog, ACME, Postfix
