I just setup my mac for development and used this exact gemfile previously and it worked fine. I am not sure what I am doing wrong.
Victorias-MacBook-Pro:sa
You're running Ruby 1.8 and the syntax attribute:
requires ruby 1.9. You will need to change
gem 'cucumber-rails', '1.2.1', require: false
to
gem 'cucumber-rails', '1.2.1', :require => false
Or install Ruby 1.9 (maybe using RVM or rbenv) and run bundle install
again. This would be a much bettter option if it's a new project.