title: laravel backpack crud display relationship in list view filter by and update
body: <p>How can you display relationships fields and filter by in the list and update views? </p>
  
  <p>lets say I have a transactions table </p>
  
  <pre><code>Id, customer_id,  product_id, purchase_date, payment_status
  </code></pre>
  
  <p>a customer table</p>
  
  <pre><code>Id, first_name, last_name, email, password
  </code></pre>
  
  <p>a products table</p>
  
  <pre><code>Id, product_name, product_description, product_price, stock
  </code></pre>
  
  <p>for example. And I wanted to show in my transactions view:</p>
  
  <pre><code>ID, customer.first_name customer.last_name, product.product_name, purchase_date, payment_status
  </code></pre>
  
  <p>and wanted to filter the results by customer name and product name, I have read through the docs and cannot see how to achieve this.</p>