Connecting access_token records with existing users

[jspooner]

I came up with a quick little method to check a facebook users email address agains the existing users table to avoid duplicate user records.

This change would need to be scaled out to all the different oauth and open id providers. Since each provider has a different method to retrieve the users email address my code should probably be refractored.

If you have any insight to this problem let me know. I'd be happy extend this functionality.

[kimptoc]

Sounds good to me :)