title: What's the best the approach to add an extra attribute field in Drupal Commerce?
body: <p>I'm using Drupal Commerce and i have a product type called "Painting" this product type does not have an attribute fields, I'm using inline_entity_form module so i can show the product add form within the node add form for my product display content type.</p>
  
  <p>The product in the site is the painting itself, it may come with a frame or without a frame (the user can choose) and the price will change based on the user's choice, <strong>how can i add such field without using attributes fields?</strong> as attributes fields requires that the site admin to add many products and put them in one product display, i just want to keep it simple to the site admin, to make him add the product in the same way he adds a node.</p>
  
  <p>Thank you.</p>