anchor.diff:  RUN gem install rake bundler rdoc --no-rdoc --no-ri
   RUN /usr/local/rbenv/bin/rbenv rehash
   
  -## Fix shebang lines in rake and bundler so that they're run with the currently
  -## configured default Ruby instead of the Ruby they're installed with.
  +# Fix shebang lines in rake and bundler so that they're run with the currently
  +# configured default Ruby instead of the Ruby they're installed with.
   RUN sed -i 's|/usr/bin/env ruby.*$|/usr/bin/env ruby|; s|/usr/bin/ruby.*$|/usr/bin/env ruby|' \
     /usr/local/bin/rake /usr/local/bin/bundle /usr/local/bin/bundler
   
  -#   Common development headers necessary for many Ruby gems,
  -#   e.g. libxml for Nokogiri.
  +# Common development headers necessary for many Ruby gems,
  +# e.g. libxml for Nokogiri.
   RUN /build/devheaders.sh
   
  -#   Node.js and Meteor support.
  +# Node.js and Meteor support
   RUN /build/nodejs.sh
   
  -# Clean up APT when done.
  +# Clean up APT when done
   RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
  
positive.code: MAINTAINER Sascha Faun Winter <github@faun.me>
  # VERSION 0.1.0
  
  # Set correct environment variables.
  ENV HOME /root
  ENV DEBIAN_FRONTEND noninteractive
  RUN apt-get update -q
  
  # Use baseimage-docker's init process.
  CMD ["/sbin/my_init"]
  
  #   Build system and git.
  RUN /build/utilities.sh
  
  # Install rbenv
  
negative.code: # Add rbenv to the PATH
  RUN echo 'export PATH="/usr/local/rbenv/bin:$PATH"' >> ~/.bashrc
  
  # Install ruby-build
  RUN mkdir -p /usr/local/rbenv/plugins
  RUN git clone https://github.com/sstephenson/ruby-build.git /usr/local/rbenv/plugins/ruby-build
  RUN /usr/local/rbenv/plugins/ruby-build/install.sh
  