anchor.diff:  
   ADD . /app
   
  -CMD rm /app/.ruby-version
  +RUN rm /app/.ruby-version
   
   ENTRYPOINT bundle exec rails s
   
  
positive.code: ENV RUBY_VERSION 2.0.0-p594
  ENV RAILS_ENV development
  
  # install software-properties-common for add-apt-repository
  RUN apt-get update -qq
  RUN apt-get install -qq -y software-properties-common
  
  # install ruby
  RUN apt-get -qq -y install autoconf bison build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev
  
  RUN add-apt-repository -y ppa:chris-lea/node.js
  # RUN add-apt-repository -y ppa:nginx/stable
  RUN apt-get update -qq
  
  # install nodejs
  RUN apt-get install -qq -y nodejs
  
  RUN rbenv install $RUBY_VERSION
  
negative.code: RUN add-apt-repository ppa:git-core/ppa
  RUN apt-get update -qq
  RUN apt-get -qq -y install git libpq-dev postgresql-client 
  
  RUN echo "gem: --no-rdoc --no-ri" >> ~/.gemrc
  
  WORKDIR /app
  
  RUN gem install bundler
  
  