Custom Timestamp attributes for Activerecord

In ActiveRecord, when working with legacy database and the existing database
uses different fields for last_update and created_at, how do you specify the
correct column names for ActiveRecord to properly record timestamps?

  # in your config/initializers directory, create a new file
  # `active_record_patch.rb`

  # overload
  module ActiveRecord
    module Timestamp
_     private
        def timestamp_attributes_for_create #:nodoc:
          [:created_at, :created_on, :create_date, :post_date]
        end
        def timestamp_attributes_for_update #:nodoc:
          [:modtime, :updated_on, :modified_at, :updated_at, :last_update]
        end
    end
  end