Add CLI text editors to r-session-complete image #52
Description
Original issue: rstudio/rstudio-docker-products#873
Currently, it appears that our r-session-complete images don't include any way to edit text on the CLI, no vim or nano. We should add these to images since they are relatively small and cause a poor admin and user experience when trying to verify pod configuration files and other pod specific details. Also some users prefer to do some editing with these files.