RailsApps/rails_apps_composer — pull request #164 by dalton (2013-02-20 15:25:54+00:00)
Title: Update recipes/extras.rb

I added a :platforms group to the binding_of_caller gem to prevent it from being installed in non-MRI/Rubinius Ruby implementations (JRuby, et al)

https://github.com/banister/binding_of_caller

http://gembundler.com/man/gemfile.5.html