title: How to implement Oauth2 Provider in REST Api Server?
body: <p>I am developing REST API Server in Node.js and it is almost Ready. Now I am trying to implement Authentication to API server. I decided to use OAuth2 for this. I think I will be Using grant type password, as most of the Apps that will use my service will be under my control. 
  There are some modules available <a href="https://github.com/jaredhanson/oauth2orize" rel="nofollow">https://github.com/jaredhanson/oauth2orize</a>, I am confused on storing access token for the authorised users and mantaining sessions. As this is REST server do i need to mantain the Session, Or should i just store active tokens and related users to db and check for each request if they are valid or not?</p>