title: Ruby on Rails Devise code after login
body: <p>I have an RoR app using Devise for logins.  There is some code that is executed when a new User record is created, by being put in the user.rb file as an after_create call/macro/whatever.  I need to make this code run after each login, instead of running on new user creation.</p>
  
  <p>With some Googling, it seems that one option is to place Warden callbacks in the devise.rb code.  My questions are:</p>
  
  <ol>
  <li>Is this right, and/or is there a better way to do this?</li>
  <li>If this is the right approach ...
  <ul>
  <li>Should the Warden::Manager... method defs go in devise.rb inside of Devise.setup, or after it?</li>
  <li>Is after_authentication the callback I should use?  I'm just checking to see if a directory based on the user's name exists, and if not, creating it.</li>
  </ul></li>
  </ol>