title: Rails and Devise: login without login/password but using a specific URL?
body: <p>I would like to create URL's that, if the user clicks, log them in automatically without having to supply a username and or password.</p>
  
  <p>Anyone know how to accomplish this in Devise with Rails 3?
  Preferrable the URL's that are generated to login a user are as short as possible. </p>