How to install additional R packages into custom notebook image?

I customize the user notebook environment like so (installing custom python packages)

How can I install custom R packages? Specifically, I am looking to install:

  • reticulate
  • mvtnorm
  • gdata
  • matrixcalc
  • gtools
  • mpoly
  • moments

These are available in CRAN

Have you looked at https://github.com/rocker-org/rocker/blob/c8a32175e360ad9bba68d9e25235fd982bf3816b/r-base/3.6.3/Dockerfile and https://github.com/rocker-org/rocker-versioned/blob/896b455f2bebb0d65296c962b8fbb9d33b8a5f85/tidyverse/latest.Dockerfile ?