Oauth2 Google?

Hello, I'm wondering if I could get help, or find documentation(even just a draft) on setting up Oauth2 on a freeradius server(omniauth?). I'm looking to use my google apps domain user database, to manage users, and control access through an Untangle captive portal, which is already setup(then probably drop the portal and do EAP, though I'll play to see if I can start with EAP). Also if I'm on the completely wrong/old track, I'm no too worried about changing the plan now. Thanks for the time/sorry for not lurking more before posting, Jesse