Merge pull request #72 from zohlgren/fix_asset_tag_helper

Fix for #45

Author: guilleiguaran

lib/sprockets/rails/helper.rb

@@ -7,6 +7,7 @@ module Rails
     module Helper
       if defined? ActionView::Helpers::AssetUrlHelper
         include ActionView::Helpers::AssetUrlHelper
+        include ActionView::Helpers::AssetTagHelper
       else
         require 'sprockets/rails/legacy_asset_tag_helper'
         require 'sprockets/rails/legacy_asset_url_helper'
@@ -22,7 +23,7 @@ def self.included(klass)
           klass.class_eval do
             alias_method :assets_environment, :environment
             def assets_manifest; end
-            class_attribute :config, :assets_prefix, :digest_assets
+            class_attribute :config, :assets_prefix, :digest_assets, :debug_assets
           end
         else
           klass.class_attribute(*VIEW_ACCESSORS)