title: How to get child nodes for parent model with rabl output
body: <p>I am building a Rails 3 web app and I am using Rabl for JSON output.
  In my app I got the following tables:</p>
  
  <p>Account
   - Can have one or many clients
   - Can have one or many projects</p>
  
  <p>Clients
   - Belongs to an account</p>
  
  <p>Project
   - Belongs to an account</p>
  
  <p>When I fetch a single project I need to get an array of all clients that belongs to the current account along with the project data. How can I do this using Rabl?</p>