Let's actually use rvm this time.

cruise_config.rb

 require 'fileutils'
 
 Project.configure do |project|
-  project.build_command = 'cd .. && cd work && gem update --system && ruby lib/cruise/build.rb'
+  project.build_command = 'source /usr/local/rvm/scripts/rvm && rvm use ruby-1.8.7-p249 && gem update --system && ruby lib/cruise/build.rb'
 end