title: Rails ownership chain and STI
body: <p>Given the following tables:</p>
  
  <pre><code>users
  organizations
  accounts
    owner_id
    owner_type
  profiles
  </code></pre>
  
  <p>Where Accounts can be owned by either a User or an Organization, and each Account has exactly one Profile, is it possible to do STI in Rails on the Profile without needing a "type" field?  IE, can I have OrganizationProfile and UserProfile classes that get loaded based on the ownership chain, or do I need to have a redundant "type" field on the profile?</p>