title: How do I deploy my rails app to Heroku using an existing SQL database?
body: <p>I have an existing MySQL database and would like to build a Rails app on top of it. How do I deploy my app to Heroku but still use my existing database instead of the default PostgreSQL database?</p>
  
  <p><strong>EDIT</strong>
  Rephrasing the question slightly (formerly, it was "Is it possible to deploy...").</p>