Add "scope" method

README.markdown

@@ -126,12 +126,12 @@ class PostSerializer < ActiveModel::Serializer
 
   # only let the user see comments he created.
   def comments
-    post.comments.where(:created_by => options[:scope])
+    post.comments.where(:created_by => scope)
   end
 end
 ```
 
-In a serializer, `options[:scope]` is the current authorization scope (usually
+In a serializer, `scope` is the current authorization scope (usually
 `current_user`), which the controller gives to the serializer when you call
 `render :json`
 

lib/active_model/serializer.rb

@@ -103,7 +103,7 @@ module ActiveModel
   #       end
   #
   #       def author?
-  #         post.author == options[:scope]
+  #         post.author == scope
   #       end
   #     end
   #
@@ -520,6 +520,11 @@ module ActiveModel
       hash
     end
 
+    # Returns options[:scope]
+    def scope 
+      @options[:scope]
+    end
+
     alias :read_attribute_for_serialization :send
 
     # Use ActiveSupport::Notifications to send events to external systems.

test/serializer_test.rb

@@ -94,6 +94,11 @@ class SerializerTest < ActiveModel::TestCase
     has_many :comments, :serializer => CommentSerializer
   end
 
+  def test_scope_works_correct
+    serializer = ActiveModel::Serializer.new :foo, :scope => :bar
+    asser_equal serializer.scope, :bar
+  end
+
   def test_attributes
     user = User.new
     user_serializer = DefaultUserSerializer.new(user, {})