title: Linking models to parent in Laravel
body: <p>Is there a quick way to link models to a parent model?</p>
  
  <p>For example, I have a <code>Product</code> model, where each row in the product table has a <code>product_type</code>.</p>
  
  <p>I want to be able to access different product_types using their own model, and have access to the native query builder. E.g. I want to be able to access <code>Event</code> in the following way:</p>
  
  <pre><code>// Calling the Event model
  Event::all();
  
  // This would be equivalent to
  Product::where('product_type', 'event')-&gt;get();
  
  // Going deeper
  Event::where('name', 'Some Title')-&gt;get();
  
  // Should result in
  Product::where('product_type', 'event')-&gt;where('name', 'Some Title')-&gt;get();
  </code></pre>
  
  <p>Is there a quick way of defining this relationship in the Event or Product models so that the query builder still works, other than manually redefining every single method in the Event model?</p>