Don't raise AR::RecordNotFound if there is no id

app/controllers/application_controller.rb

@@ -9,7 +9,7 @@ class ApplicationController < ActionController::Base
   private
 
   def current_user
-    @current_user ||= User.find(session[:user_id]) if session[:user_id]
+    @current_user ||= User.first(:id => session[:user_id]) if session[:user_id]
   end
 
   def current_user=(user)