zquestz/omniauth-google-oauth2 — pull request #78 by bcoe (2013-11-06 19:27:00+00:00)
Title: Changed prompt authorize option to approval_prompt

Reading through the Google documentation, I believe the prompt option should be approval_prompt:

https://developers.google.com/accounts/docs/OAuth2WebServer#formingtheurl

This option is important, so that a missing or invalid refresh_token can be updated.