title: Refresh tokens asp.net identity
body: <p>I'm working with Asp.net MVC 5 / Web API 2.</p>
  
  <p>I'm authenticating users from an android app.
  I'm using Asp.net Identity and OWIN....The thing I can't wrap my head around is token authentication...</p>
  
  <p>I've got this successfully working so that a long lived access token is sent to the client. And it can make authorized calls.</p>
  
  <p>The part I'm not sure is refresh tokens. When an access token expires what should I do? do i need to store anything in DB tables? Just need a rough idea on what i need to implement</p>