Update ib-ruby.gemspec

 gem.add_dependency 'activerecord', '=> 3.2.0'
Makes bundler install the last activerecord version, that in the moment of writings this is 4.0.0, this activerecord version breaks this gem because of change in regular expressions see this http://dev.mensfeld.pl/2013/07/upgrading-to-rails-4-0-from-rails-3-2-test-case-part-ii-assets-models/#regexp