How to add dependencies on a bioconductor package

Our R package bioimagetools is on CRAN now. The package depends on EBImage, which is an Bioconductor package. The problem is, installing from CRAN via

install.packages("bioimagetools")

will only install dependencies from CRAN, not from Bioconductor (also Bioconductor is considered a „mainstream repository“). Some googling showed that I am not the only one with this issue. So here is the solution: In the DESCRIPTON file, add the line

Additional_repositories: https://bioconductor.org/packages/3.3/bioc/

The „Additional_repositories“ field was new to me. It will check the repositories with the given URL for the dependencies in the DESCRIPTION file. The more general „https://bioconductor.org/packages/bioc“ will also work, but throw a warning.