Ensure $root/app/assets

Closes #154

Author: josh

lib/sprockets/railtie.rb

@@ -41,7 +41,8 @@ def assets
 module Sprockets
   class Railtie < ::Rails::Railtie
     LOOSE_APP_ASSETS = lambda do |filename, path|
-      path =~ /app\/assets/ && !%w(.js .css).include?(File.extname(filename))
+      path.start_with?(::Rails.root.join("app/assets").to_s) &&
+        !%w(.js .css).include?(File.extname(logical_path))
     end
 
     class OrderedOptions < ActiveSupport::OrderedOptions