I'm in the process of developing a web app that shall initially utilize Facebook's API (sign in with Facebook), but will eventually expand to other APIs like Twitter. I've never developed an app using a third-party sign-in service.

I am curious to learn about people's approaches to developing an expandable platform, particularly with database design and a unified users table across these platforms.

When signing in with Facebook, should the web app create and store a local user record? Or is session management handled exclusively by the Facebook API?

Any tutorials and/or links are appreciated. Thanks in advanced.