Adding id_token to session info

[nirshubz]

Really cool library, helped me out a lot!

It would be really helpful if you could add id_token to the session info.
We are using it in django admin to access other authorised services outside the django server using the token.

To access it in my app I added the following line to process_login:
user_info['id_token'] = token_info.get('id_token')

Thanks!