title: New rails 4.1 mailer preview action not found error
body: <p>Rails has 607 open issues...so, rather than plugging that hole even more I though Id try here first.  I have upgraded to 4.1 and am implementing rails mailer previews.  I tried upgrading my existing mailer and adding tests/mailers/previews directory.  When that gave the following error I tried generating a new mailer.  Same error.</p>
  
  <pre><code> class NotifierPreview &lt; ActionMailer::Preview
      def welcome
        Notifier.welcome(User.first)
      end
    end
  </code></pre>
  
  <p>results in this error:</p>
  
  <pre><code> The action 'notifier' could not be found for Rails::MailersController
  </code></pre>
  
  <p>I've tried searching google, the docs, stack overflow, but nothing eludes to this error.</p>
  
  <p>Anyone experience this or have any ideas?</p>