title: How do I retroactively add a primary key to my table in rails?
body: <p>I've created a table without a primary key (:id => false), but now it has come back to bite my ass. </p>
  
  <p>My app is already in production and I can't just drop it and recreate another one.  </p>
  
  <p>Is there a way to run a migration to add another auto increment primary key column to my table?</p>