switching my rails 3.2.12 project to ruby 2.0.0 fails a test:
NoMethodError:
private method `initialize_dup' called for #<Event:0x007fe06c809428>
this is the code that gets called: https://github.com/phoet/on_ruby/blob/master/app/models/event.rb#L86
looks like initialize_dup is now a private method :sadpanda: