That TinyMCE plugin installs much easier if you have your project under Subversion, so I'm joining the modern world and leaving CVS. Here's some links:

How to Use Rails with Subversion
Put your homedirectiory under Subversion - I heard about this guy years ago when he was talking about doing the same thing with CVS.
Subversion Book - For version 1.1 of Subversion
External Definitions with Subversion