title: ReferenceError: Chartkick is not defined
body: <p>I am using <a href="https://github.com/ankane/chartkick" rel="noreferrer">chartkick</a> gem to display chart. I have followed the proper installation documentation but whenever I am trying to use their methods like </p>
  
  <pre><code>timeline [["Washington", "1789-04-29", "1797-03-03"], ["Adams", "1797-03-03", "1801-03-03"], ["Jefferson", "1801-03-03", "1809-03-03"]]
  </code></pre>
  
  <p>It's showing error in the firebug
  <strong>ReferenceError: Chartkick is not defined</strong></p>