[Note: I'm making an assumption here that you know and understand Bundler and RVM.]
[Also: Cruise may or may not be running on RVM]
Create and check in a .rvmrc file in your rails root directory. Here’s an example.
Then, add a project build command to your cruise_config.rb file.
Project.configure do |project| project.build_command = './cruise_build.sh' end
Finally, create a cruise_build.sh file. The bash script setups rvm and just calls your cruise control build task.
[Note: Your cruise rake task should probably call Bundler's "bundle install".]
#!/bin/sh source $HOME/.rvm/scripts/rvm && source .rvmrc rake cc:build
…and your cruise project builder is now using RVM!