anchor.diff:      && apt-get update \
       && apt-get install -y docker-engine
   
  -## emacs
   
  -RUN apt-get install -y emacs
  +## (because --deps TRUE can fail when packages are added/removed from CRAN)
  +RUN apt-get autoclean \
  +    && apt-get clean \
  +    && rm -rf /var/lib/apt/lists/ \
  +    && rm -rf /tmp/downloaded_packages/ /tmp/*.rds
   
   CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]
positive.code: 
  ## 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
  
  
  ##################
  
negative.code: RUN R -e "devtools::install_github('road2stat/liftr', ref = 'devel')"
  RUN R -e "devtools::install_github('rstudio/packrat')"
  
  RUN apt-get -y install unp emacs
  
  ## install docker
  RUN apt-get update \
  