Introducing the Dockerfilemerge gem

require 'dockerfilemerge'

s2 =<<EOF
# Dockermergefile

INCLUDE
  https://raw.githubusercontent.com/hypriot/rpi-ruby/master/Dockerfile
  https://raw.githubusercontent.com/acencini/rpi-python-serial-wiringpi/master/Dockerfile

MAINTAINER James Robertson <james@jamesrobertson.eu>

RUN gem install humble_rpi
RUN gem install dynarex
EOF

puts DockerfileMerge.new(s2).to_s