title: How to declare a nested resource in activeadmin?
body: <p>I have a resource called User and another one called Order.</p>
  
  <p>I want Order to be nested inside Users so I can have these routes:</p>
  
  <pre><code>/users
  /users/:id
  /users/:id/new
  /users/:id/edit
  /users/:user_id/orders
  /users/:user_id/orders/:id
  /users/:user_id/orders/:id/new
  /users/:user_id/orders/:id/edit
  </code></pre>
  
  <p>How can I do that with activeadmin?</p>