Documentation confusion

When learning the consumer side of this in IRB, I was confused by the readme code example:

```
  @access_token = @request_token.get_access_token
```

where for me it needed to be:

```
  @access_token = @request_token.get_access_token :oauth_verifier => '[verifier_from_provider_callback]'
```

Maybe I'm missing something?

Nice work on this, BTW!

Cheers,
Luke
