Passport authorize documentation uses undefined variable in code sample

The authorize API call is described here: http://passportjs.org/docs/authorize

In the callback code sample a follow on middleware method is used to redirect after the updated account is saved to the database:

```
account.save(function(err) {
if (err) { return self.error(err); }
self.redirect('/');
});
```

However self is not defined. Instead the save callback should use res.redirect('/'), where res is available because it is defined in the function that encloses the save callback

Open the authorize documentation at http://passportjs.org/docs/authorize and inspect the callback code sample. Confirm which response object is available in the enclosing function, update the save callback so it no longer references an undefined variable, and verify the sample has no remaining undefined reference.

Written by the indexing model from the issue text.