title: Can I have multiple (access_token, refresh_token) to serve the same user on different client/devices with doorkeeper?
body: <p>I'm in the process of securing a Rails api-only app, and I'd like to do so with OAuth2 (password flow) and using <a href="https://github.com/doorkeeper-gem/doorkeeper" rel="nofollow">Doorkeeper</a>. Ignoring the fact that I can't find sufficiently clear docs on how to do this, the use case I have in mind is one where there are multiple clients on multiple devices/platforms (e.g. Android, iOS, browser) and they all require a user to login. I want to be able to issue a new (access_token, refresh_token) pair for every new login, and they all should identify the user for whom the pair was created. That is, if Alice logs in through Android and iOS, and Bob through two browsers, I want a record such as</p>
  
  <pre><code>| user_id | access_token | refresh_token | client_id        |
  |---------|--------------|---------------|------------------|
  | Alice   | a6d7f82h3hf  | d8f6g8d0e3    | Android-h3j4k5l6 |
  | Alice   | 3j4k5j3l5k3  | 1hnrbtj5kc    | iOS-j2k35h3n     |
  | Bob     | 513lkhbjkf3  | rhj2345bvj    | web-43nfm23      |
  | Bob     | nbv234nbv65  | cbv124cr64    | web-gc62jh4      |
  </code></pre>
  
  <p>(data completely made up). Can someone provide a straight answer, and possibly point me to docs, a guide, a tutorial relevant to this? I know I can roll out my own auth system implementing this particular use case, and I have done so in the past, but with this one I'd like the flexibility of OAuth2 for future improvement.</p>