upgrade to rails3, but grip is broken

app/controllers/pages_controller.rb

@@ -10,7 +10,7 @@ class PagesController < ApplicationController
   end
   
   def show    
-    @page = Page.find_by_full_name(params[:page_name].join("/"))
+    @page = Page.find_by_full_name(params[:page_name])
     render_liquid_page
   end