I believe that would allow for versions up to `4.x`, and `ActiveSupport::SecureRandom` is deprecated in `3.1`:
https://github.com/rails/rails/blob/3-1-stable/activesupport/lib/active_support/secure_random.rb

Actually, I just did a quick gut-check, as it seems that `bundle exec pwqgen.rb` works with the osx system ruby (1.8.7) even without installing activesupport... I'll need to look into this. I'll try to sort it out tomorrow, but thanks for taking a look at this :)