title: Devise: undefined method `user_signed_in?' for ApplicationController:Class
body: <p>I'm getting the above error with Rails 3.1.1 and Ruby 1.9.2.  I've spent the last hour looking and the main things I've found were:</p>
  
  <ol>
  <li><p><code>clear_helpers</code> in ApplicationController can cause the helpers to not load.  My code isn't using that and I don't believe the gems I've installed are either.</p></li>
  <li><p>Missing <code>devise_for</code> in routes.rb.  I have <code>devise_for :users</code></p></li>
  <li><p>Missing 'database_authenticatable' in my Users model.  I have in my users.rb :  </p>
  
  <p>devise :database_authenticatable, :registerable,
    :recoverable, :rememberable, :trackable, :validatable</p></li>
  <li><p>My behavior matches exactly what's described in <a href="http://groups.google.com/group/plataformatec-devise/browse_thread/thread/e87dd5d00ce0217c" rel="nofollow">this email thread</a> except <code>signed_in? :user</code> doesn't work for me either.  However, <code>Devise.mappings</code> does show the user mapping.</p></li>
  </ol>
  
  <p>Any ideas on what could be wrong?  Even a hack for current_user would help me greatly as I have to get some functionality running ASAP.</p>