use on_load for rails 3 and to_prepare for rails 2

Author: nightpool

lib/attr_encrypted/adapters/active_record.rb

@@ -133,10 +133,17 @@ def method_missing_with_attr_encrypted(method, *args, &block)
     end
   end
 
-  Rails.configuration.to_prepare do
-    ActiveRecord::Base.class_eval do
+  if defined?(ActiveSupport.on_load)
+    ActiveSupport.on_load(:active_record) do
       extend AttrEncrypted
       extend AttrEncrypted::Adapters::ActiveRecord
     end
+  else
+    Rails.configuration.to_prepare do
+      ActiveRecord::Base.class_eval do
+        extend AttrEncrypted
+        extend AttrEncrypted::Adapters::ActiveRecord
+      end
+    end
   end
 end