Refactor and use class_attribute

activerecord/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
-*   Added a `stored_attributes` hash which contains the attributes stored
-    using ActiveRecord::Store. This allows you to retrieve the list of
-    attributes you've defined.
+*   Added `stored_attributes` hash which contains the attributes stored using
+    ActiveRecord::Store. This allows you to retrieve the list of attributes
+    you've defined.
 
-    *Joost Baaij*
+       class User < ActiveRecord::Base
+         store :settings, accessors: [:color, :homepage]
+       end
+
+       User.stored_attributes[:settings] # [:color, :homepage]
+
+    *Joost Baaij & Carlos Antonio da Silva*
 
 *   `composed_of` was removed. You'll have to write your own accessor
     and mutator methods if you'd like to use value objects to represent some

activerecord/lib/active_record/store.rb

 require 'active_support/concern'
 require 'active_support/core_ext/hash/indifferent_access'
+require 'active_support/core_ext/class/attribute'
 
 module ActiveRecord
   # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
@@ -42,7 +43,7 @@ module Store
     extend ActiveSupport::Concern
 
     included do
-      config_attribute :stored_attributes
+      class_attribute :stored_attributes
       self.stored_attributes = {}
     end
 
@@ -53,7 +54,8 @@ def store(store_attribute, options = {})
       end
 
       def store_accessor(store_attribute, *keys)
-        keys.flatten.each do |key|
+        keys = keys.flatten
+        keys.each do |key|
           define_method("#{key}=") do |value|
             initialize_store_attribute(store_attribute)
             send(store_attribute)[key] = value
@@ -66,7 +68,7 @@ def store_accessor(store_attribute, *keys)
           end
         end
 
-        self.stored_attributes[store_attribute] = keys.flatten
+        self.stored_attributes[store_attribute] = keys
       end
     end