anchor.diff:  
   ## RUN Rscript -e 'source("http://bioconductor.org/biocLite.R");library(BiocInstaller); ## biocLite("sevenbridges", dep = TRUE)'
   
  -## (because --deps TRUE can fail when packages are added/removed from CRAN)
  -RUN apt-get clean \
  -##     && rm -rf /var/lib/apt/lists/ \
  -    && rm -rf /tmp/downloaded_packages/ /tmp/*.rds
  +
   
   
   ##################
  
positive.code:     && apt-get update \
      && apt-get install -y docker-engine
  
  ## emacs
  
  RUN apt-get install -y emacs
  
  CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]
negative.code: 
  ## thanks to official shiny docker file
  
  RUN apt-get autoclean \
      && apt-get clean \
      && apt-get update && apt-get install -y -t unstable \
      sudo \
      gdebi-core \
      pandoc \
  