I followed the instructions in this article on how to setup RDT in
Eclipse:
http://www-128.ibm.com/developerworks/opensource/library/os-rubyeclipse/?ca=dgr-lnxw01Ruby4Eclipse

I was able to run the unit tests but I don't know how to get the
debugger working. I am using Eclipse 3.2. Does anyone know how I can
get the debugger working? TIA.