title: How to call devise sign_in and sign_out methods of devise from another controller different from devise?
body: <p>I have a Ruby on Rails 3.0.7 application and my user authentication with <code>devise</code>but and I have an alternative <code>sign up</code> and <code>sign in</code> methods, I allow my users to sign up using their <code>Facebook</code> account then I save that login info in my <code>users</code> table the same one that devise uses to register and login users.</p>
  
  <p>Steps</p>
  
  <ol>
  <li>✔ User click on the Facebook button.</li>
  <li>✔ I save his info (name and email extracted from <code>Koala</code>) I give the user a generic password.</li>
  <li>☐ Login this new user with devise.</li>
  <li>✔ Redirect to my main controller.</li>
  </ol>
  
  <p>I'm just missing the 3rd step because I want to keep using the <code>current_user</code> helper and the <code>user_signed_in?</code> helper too.</p>
  
  <p>So how do I tell devise to sign in this user automatically from my other controller?</p>
  
  <p>I saw something like that on this question <a href="https://stackoverflow.com/q/6143814">Devise: Have multiple controllers handle user sessions</a> and it logs my user in but leads me to an blank page...</p>