anchor.diff:     R6_2.1.2.tar.gz \
      httr_1.1.0.tar.gz \
      rstudioapi_0.5.tar.gz \
  +   openssl_0.9.1.tar.gz \
      withr_1.0.0.tar.gz \
      brew_1.0-6.tar.gz \
      roxygen2_5.0.1.tar.gz \
  
positive.code: # R packages we need for devtools - and we need devtools to be able to update the rmarkdown package
  RUN DEBIAN_FRONTEND=noninteractive wget \
     http://mirrors.nics.utk.edu/cran/src/contrib/rstudioapi_0.5.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/withr_1.0.0.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/brew_1.0-6.tar.gz \
     http://mirrors.nics.utk.edu/cran/src/contrib/roxygen2_5.0.1.tar.gz \
  
negative.code:    curl_0.9.5.tar.gz \
     httr_1.1.0.tar.gz \
     rstudioapi_0.5.tar.gz \
     openssl_0.9.1.tar.gz \
     withr_1.0.0.tar.gz \
     brew_1.0-6.tar.gz \
     roxygen2_5.0.1.tar.gz \
  