[galaxy-dev] Adding tool to Galaxy

Hello, Can anyone tell me how to add a tool to Galaxy, to be shown on the panel on the left? In particular, I'd like to add the 'cuffmerge' tool to the cufflinks (RNA seq)  group under NGS:RNA Analysis. Other cufflinks tools are there (cufflinks,cuffcompare,cuffdiff), but not cuffmerge. Thank you. '