title: rake task with easy interface
body: <p>Right now I can do</p>
  
  <pre><code>rake report shipment_id=5
  
  rake report do
    id = ENV['shipment_id]
  end
  </code></pre>
  
  <p>However I want to simplify the interace to the user by having</p>
  
  <pre><code>rake report 5
  </code></pre>
  
  <p>How do I do that in rake?</p>
  
  <p>Last resort would be to use ruby and then call rake internally but I want to check if I am missing some feature of rake?</p>