It is worth noting that as of April, 2012 Google as Deprecated the OAuth version 1 API. It is still in "deprecation support" but you should move on to OAuth 2.
I updated the "twitter-oauth-sinatra" app to make it work with Google Mail and Google Apps Mail. As a bonus, it gets the email address of the user, as we do on http://silentale.com. Quite useful if you want to use IMAP or SMTP with these tokens, with the gmail_xoauth for example :)
For your local tests, launch:
CONSUMER_KEY=mydomain.com CONSUMER_SECRET=mysecret ruby app.rb
Last version of this code can be found at https://github.com/nfo/gmail-oauth-sinatra.
Contact me at http://about.me/nfo
Original README from https://github.com/mirven/twitter-oauth-sinatra:
directions using heroku for hosting:
create twitter app at http://twitter.com/apps for callback url use http://.heroku.com/auth note consumer key and consumer secret
heroku create heroku config:add consumer_key= consumer_secret= git push heroku master
inspired by http://github.com/filiptepper/sinatra-oauth-1.0a-example http://github.com/moomerman/sinitter