rails/rails — pull request #15140 by arthurnn (2014-05-16 20:42:16+00:00)
Title: Remove unecessary require

Was reading the first transaction code, and realized this require was added there and never removed.
https://github.com/rails/rails/blob/db045dbb/activerecord/lib/active_record/transactions.rb

@rafaelfranca @chancancode