Re-using shinyapps-dependencies and obstacles

[MatthiasHinz]

Issue #33 suggests to determine system dependencies based on https://github.com/rstudio/shinyapps-package-dependencies

However, as previous discussion in #33 shows, system dependencies are not explicit for all packages, for instance rgdal. That is because those dependencies that are listed in the basic Dockerfile seem to be pre-assumed, while the scripts from the 'packages' folder apply to packages that rely on additional dependencies. Hence, in order to rely on the shinyapps-package-dependencies, we would need to install all dependencies from the basic Dockerfile (or use the shinyapps image as the base image) which can result in unnecessary overhead.

Moreover, the shell scripts are made for ubuntu/linux only and therefore may not be applied to all potential base images.

• [ ] re-evaluate shinyapps-package-dependencies for re-use