title: Token Authenticatable module in Devise
body: <p>I'm starting using Devise in my Rails app, but the <code>Token Authenticatable</code>: <em>signs in a user based on an authentication token (also known as "single access token")</em> module puzzles me.</p>
  
  <p>Is the user authenticated only for his current session? If he uses now the URL containing the token, can he re-use it at a later tine and still have access, or does he get a <em>single</em> access? </p>
  
  <p>Can multiple users be authenticated at the same time, using the same token?</p>
  
  <p><em>I have searched extensively for a working example; please forgive me if this is explained elsewhere. 
  Any pointers would be more than welcomed. Thanks for your help.</em></p>