We just need to tweak the requires for it. 

/opt/boxen/rbenv/versions/2.0.0-p195/lib/ruby/gems/2.0.0/gems/activesupport-2.3.18/lib/active_support/deprecation.rb:5:in `<module:Deprecation>': undefined method `mattr_accessor' for ActiveSupport::Deprecation:Module (NoMethodError)