anchor.diff:  RUN /usr/local/rbx/bin/gem install --no-document bundler
   
   # cleanup
  -RUN rm -rf /usr/local/src/rubinius-2.5.3.tar.bz2 && \
  +RUN rm -rf /usr/local/src/rubinius-${RBX_VERSION}.tar.bz2 && \
     rm -rf /var/lib/apt/lists/* && \
     rm -rf /tmp/* && \
     rm -rf /var/tmp/*
  
positive.code: # download & install
  RUN gem install bundler
  WORKDIR /usr/local/src
  RUN wget --quiet http://releases.rubini.us/rubinius-2.5.3.tar.bz2 && \
    tar jxf rubinius-2.5.3.tar.bz2
  WORKDIR /usr/local/src/rubinius-2.5.3
  RUN curl -fsSL curl.haxx.se/ca/cacert.pem -o ./library/rubygems/ssl_certs/cacert.pem
  RUN bundle
  RUN ./configure --prefix=/usr/local/rbx --libc=/usr/lib/x86_64-linux-gnu/libc
  
negative.code: FROM ubuntu:14.04
  MAINTAINER Nathan Hopkins <natehop@gmail.com>
  ENV RBX_VERSION 2.5.8
  
  RUN apt-get -y --force-yes install lsb-release && \
    echo deb http://archive.ubuntu.com/ubuntu $(lsb_release -cs) main universe > /etc/apt/sources.list.d/universe.list && \
  