title: sails.js one to many relationship - variable owner collection attribute
body: <p>On sailsjs.org's documentation, a one to many relationship for the owning side is defined like this</p>
  
  <pre><code>//user.js
  module.exports = {
      attributes: {
          name:'STRING',
          age:'INTEGER',
          pets:{
              collection: 'pet',
              via: 'owner'
          }
      }
  }
  </code></pre>
  
  <p>'pet' is a constant, with a consistent schema on SQL databases. What if I want to have a superclass pet and subclasses with unique attributes(different number of rows)? Say I have an octopus and a dog. Dogs have 4 legs and 2 ears. Octopus have 8 tentacles. The only commonality will be abstracted into the pet class(color, name, age).</p>
  
  <p>If this is not possible, I would have to resort to something like this no?</p>
  
  <pre><code>//user.js
  module.exports = {
      attributes: {
          name:'STRING',
          age:'INTEGER',
          dogs:{
              collection: 'dog',
              via: 'owner'
          },
          octopuses:{
              collection: 'octopus',
              via: 'owner'
          }
      }
  }
  </code></pre>
  
  <p>However, this could get quite messy if I wanted to introduce more pets like eagle(can fly), parrot(can talk), and would result in many nulls if I was to use a SQL database. Perhaps mongoDB would be ideal for this?</p>