anchor.diff:  ENV NOKOGIRI_USE_SYSTEM_LIBRARIES 1
   
   # Temporarily replace ImageMagick policy file with one that fixes
  -# CVE-2016-3714
  +# CVE-2016-3714 and others.
   RUN mkdir -p /etc/ImageMagick-6 && rm -f /etc/ImageMagick-6/policy.xml
   COPY files/policy.xml /etc/ImageMagick-6/
   
  
positive.code:     rm /var/lib/apt/lists/*_*
  
  # Install node
  RUN mkdir /nodejs && curl https://nodejs.org/dist/v5.7.1/node-v5.7.1-linux-x64.tar.gz | tar xvzf - -C /nodejs --strip-components=1
  ENV PATH /nodejs/bin:$PATH
  
  # Install rbenv
  
negative.code:     rbenv global $V; \
      done
  
  # Preinstall bundler gem
  ENV BUNDLER_VERSION 1.12.5
  RUN for V in $PREINSTALLED_RUBY_VERSIONS; do \
      RBENV_VERSION=$V gem install -q --no-rdoc --no-ri bundler --version $BUNDLER_VERSION; \
      rbenv rehash; \
      done
  # Tell nokogiri >=1.6 to install using system libraries, for faster builds
  