add a second bar plot on the right side

[apastore]

Hi, Thanks for this package!
I was wondering if it would be possible to add a second barplot on the right side. ( for the Mutisig FDR plot, using a data frame of genes and FDR values)

Thanks!

[zlskidmore]

@apastore I've done this before but not without having to go in the code base itself (and extracting individual plots). In the future I am planning to attempt to implement this functionality.