title: what's the differences between helper and include in a controller?
body: <p>i'm working on refinerycms, trying to add preview feature to news like pages, i'm trying to include my own helper to a controller, 'include' does not works, but 'helper' works.</p>
  
  <p>sample code:</p>
  
  <pre><code>module Refinery
    module News
      module Admin
        class PreviewController &lt; ActionController::Base
          #include LayoutHelper # not ok
          helper LayoutHelper # Ok
        end
      end
    end
  end
  </code></pre>
  
  <p>i've read the api, helper is working like 'require and include', but i don't know the real difference here.</p>
  
  <p>thanks !</p>