anchor.diff:    && rm -rf $(ls -d ruby-* | head -n 1)
   
   # varnish
  -RUN apt-get install --assume-yes \
  +RUN apt-get update \
  +  && apt-get install --assume-yes \
       apt-transport-https \
     && curl https://repo.varnish-cache.org/GPG-key.txt \
       | apt-key add - \
     && echo 'deb https://repo.varnish-cache.org/debian/ jessie varnish-4.1' \
       >> /etc/apt/sources.list.d/varnish-cache.list \
     && apt-get update \
  -  && apt-get install --assume-yes varnish
  +  && apt-get install --assume-yes \
  +    varnish
   COPY docker/default.vcl /etc/varnish/default.vcl
   RUN varnishd -C -f /etc/varnish/default.vcl
   COPY docker/varnish_defaults /etc/default/varnish
   
   # monit
  -RUN apt-get install --assume-yes \
  +RUN apt-get update \
  +  && apt-get install --assume-yes \
       libpam-dev \
     && curl https://mmonit.com/monit/dist/monit-5.16.tar.gz \
       | tar xz \
  
positive.code: 
  ENV RAILS_SERVE_STATIC_FILES true
  
  RUN apt-get install --assume-yes \
      libpq-dev \
      libsqlite3-dev \
    && export LDFLAGS=-lMagickWand-6.Q16 \
  
negative.code: COPY docker/sources.list /etc/apt/sources.list
  
  # packages
  RUN apt-get update \
    && apt-get install --assume-yes \
      build-essential \
      curl \
      memcached \
      runit
  
  # imagemagick
  RUN apt-get update \
    && apt-get install --assume-yes \
      inkscape \
      libbz2-dev \
      libfftw3-dev \
  