Support dirty tracking with rails 3.2.9.rc1

Starting with rails 3.2.9.rc1 the method #field_changed?
was renamed to #_field_changed?

rails/rails#3544

lib/active_record/connection_adapters/oracle_enhanced_dirty.rb

@@ -5,7 +5,7 @@ module OracleEnhancedDirty #:nodoc:
       module InstanceMethods #:nodoc:
         private
 
-        def field_changed?(attr, old, value)
+        def _field_changed?(attr, old, value)
           if column = column_for_attribute(attr)
             # Added also :decimal type
             if (column.type == :integer || column.type == :decimal) && column.null && (old.nil? || old == 0) && value.blank?
@@ -35,5 +35,10 @@ def field_changed?(attr, old, value)
 if ActiveRecord::Base.method_defined?(:changed?)
   ActiveRecord::Base.class_eval do
     include ActiveRecord::ConnectionAdapters::OracleEnhancedDirty::InstanceMethods
+    # Starting with rails 3.2.9 the method #field_changed?
+    # was renamed to #_field_changed?
+    if private_method_defined?(:field_changed?)
+      alias_method :field_changed?, :_field_changed?
+    end
   end
 end