anchor.diff:      nodejs \
       phantomjs
   
  -# Install ruby-2.1.2.
  +# Install ruby.
   RUN curl -O http://ftp.ruby-lang.org/pub/ruby/$RUBY_MAJOR/ruby-$RUBY_MINOR.tar.gz && \
       tar -xzvf ruby-$RUBY_MINOR.tar.gz && \
       cd ruby-$RUBY_MINOR && \
  
positive.code:     make install && \
      cd .. && \
      rm -r ruby-$RUBY_MINOR ruby-$RUBY_MINOR.tar.gz && \
      echo 'gem: --no-document' > /usr/local/etc/gemrc
  
  # Install bundler
  RUN gem install bundler
  
  # Copy the Gemfile and Gemfile.lock into the image.
  
negative.code: FROM ubuntu:14.04
  
  # Set ruby version.
  ENV RUBY_MAJOR 2.1
  ENV RUBY_MINOR 2.1.2
  
  