[galaxy-user] Adding a custom genome for using MACS in Galaxy

I have  a chipseq data which ha sbeen alined against bacterial genome. I am trying to figure out how I can use peak calling MACS in Galaxy main server. Do I need to use the bactaerial genome (in genome option of data uplaod) in uplaoding the data. Could some one diect me if I can add my own custom genome for MACS program with in Galaxy main.   Thanks