Allow inheritance in decent configurations

Fixes #53

lib/decent_exposure/expose.rb

@@ -5,7 +5,9 @@ module DecentExposure
   module Expose
     def self.extended(base)
       base.class_eval do
-        class_attribute :_default_exposure
+        class_attribute :_default_exposure, :_decent_configurations
+        self._decent_configurations ||= Hash.new(Configuration.new)
+
         def _resources
           @_resources ||= {}
         end
@@ -17,10 +19,6 @@ def _exposures
       @_exposures ||= {}
     end
 
-    def _decent_configurations
-      @_decent_configurations ||= Hash.new(Configuration.new)
-    end
-
     def decent_configuration(name=:default,&block)
       _decent_configurations[name] = Configuration.new(&block)
     end

spec/fixtures/controllers.rb

@@ -97,6 +97,8 @@ class DuckController < BirdController
   expose(:bird) { "Duck" }
   expose(:ducks) { DuckCollection.new }
   expose(:duck)
+
+  expose(:custom_from_config, :config => :custom)
 end
 
 class MallardController < DuckController; end

spec/rails_integration_spec.rb

@@ -97,6 +97,10 @@
     it "allows overriding exposures" do
       controller.bird.should == "Duck"
     end
+
+    it "inherits decent configurations" do
+      controller.custom_from_config.should == "custom_from_configshow"
+    end
   end
 
   describe "collection scope" do