rails guides - getting started - section 10 security

The example doesn't work as described for me; not sure if I haven't
followed it right, or there's a problem with the code. Can someone
help me to determine what the problem is.

Specifically, after adding the authentication code to the
PostsController, with this line:

before_filter :authenticate, :except => [:index, :show]

The guide says that "we want the user to be authenticated on every
action, except for index and show", however, it only authenticates on
the new post and edit options; it doesn't authenticate on destroy.

Sincere thanks in advance to anyone who can help shed light on this
issue! :slight_smile:

Here's my code: