title: Heroku: Cannot run more than 1 Free size dynos
body: <p>I was trying to run </p>
  
  <pre><code>heroku run rake db:migrate
  </code></pre>
  
  <p>And was getting the error </p>
  
  <blockquote>
    <p>Cannot run more than 1 Free size dynos.</p>
  </blockquote>
  
  <p>See below for how to fix...</p>