How to use Rails 3's ActiveSupport core extensions outside Rails [duplicate]

I'm having a problem using ActiveSupport's core extensions on a gem I am developing.

I had it working with AS 2.3.8, but as soon as I wanted to port it to 3b4, the extensions stopped working and my test results are filled with lines such as:

undefined method `blank?' for "something":String

I've included it via

gem "activesupport"

followed by

require "active_support"

Is there anything else I need to call to include those extensions?

ActiveSupport is more separate now in Rails 3.

If you want the all active_support thing, you can require 'active_support/all' now.

But if you want only the blank? method, you can try

require 'active_support/core_ext/string'