title: Web2py: how to config menu.py to add link to an external link
body: <p>I have just started learning the web2py framework from example, I saw that when the menu.py is configured as following: </p>
  
  <pre><code>response.menu = [
      (T('Index'), False, URL('default','index'),[]),]
  </code></pre>
  
  <p>Then there will be an item show in the menu bar, linking to:</p>
  
  <blockquote>
    <p>%website%/%application name%/default/index</p>
  </blockquote>
  
  <p>So here is the question, how to config the menu.py file so as to add an item to link to an external link? Say: www.google.com</p>