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: RUN R -e "devtools::install_github('road2stat/liftr', ref = 'devel')"
  RUN R -e "devtools::install_github('rstudio/packrat')"
  
  RUN apt-get -y install unp
  
  ## install docker
  RUN apt-get update \
  
negative.code:     && apt-get update \
      && apt-get install -y docker-engine
  
  
  ## (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"]