Empty continuation line found in dockerfile

[Mike Kusold]

While building the image on docker 18.09.0:

[WARNING]: Empty continuation line found in:   
    RUN apk add --no-cache ruby ruby-json ruby-io-console curl-dev lighttpd php7-cgi php7-json php7-curl php7-mbstring busybox-suid fail2ban ca-certificates wget tzdata shadow && apk add --no-cache --virtual build-dependencies ruby-dev ruby-bundler libc-dev make gcc && gr
oupmod -g 1000 users && useradd -u 99 -U -d /config -s /bin/false xyz && groupmod -o -g 100 xyz && usermod -G users xyz && mkdir /run/lighttpd /var/run/fail2ban && rm /etc/fail2ban/jail.d/* && cp /opt/f2b/fail2ban.local /opt/f2b/jail.local /etc/fail2ban/ && cp /opt/f2b/no
wshowing.conf /etc/fail2ban/filter.d/ && cp /opt/f2b/iptables-common.conf /etc/fail2ban/action.d/ && cp /opt/smtp.rb /usr/lib/ruby/2.3.0/net/ && bundle config --global silence_root_warning 1 && cd /opt/gem ; bundle install && apk del --purge build-dependencies
[WARNING]: Empty continuation lines will become errors in a future release.

[El Brento]

Thanks for the info.
Looks like docker has changed their syntax a little bit and they don't want blank lines inside the RUN command of a dockerfile anymore.

Was nice for readability, but I guess I'll update it to not have the spaces anymore.

[El Brento]

Dockerfile updated in v2-dev branch. Will be pushed to main v2 branch after combining other changes,