cached slugs speed things up

db/migrate/5_add_cached_slugs.rb

@@ -0,0 +1,11 @@
+class AddCachedSlugs < ActiveRecord::Migration
+  def self.up
+    add_column :blog_categories, :cached_slug, :string
+    add_column :blog_posts, :cached_slug, :string
+  end
+
+  def self.down
+    remove_column :blog_categories, :cached_slug
+    remove_column :blog_posts, :cached_slug
+  end
+end