Rail3 beta3 require 'activesupport' - no such file to load

If I go into irb in rails3 beta3 and type in require 'activesupport'
it says:
  LoadError: no such file to load -- activesupport

What is the problem? Have I done something wrong?

Bundle show activesupport works properly and tells me where the gem

I think I have found the answer.
1) It first require rubygens to be loaded
2) rails3 has deprecated activesupport and requires active_support