.html

Added the snippet below my text area
             <script type="text/javascript">
               var editor = CodeMirror.fromTextArea(document.getElementById("source"), {
               });
             </script>
And added 
         <script src="/static/codemirror/lib/codemirror.js"></script>
         <link rel="stylesheet" href="/static/codemirror/lib/codemirror.css">
         <script src="/static/codemirror/mode/javascript/javascript.js">
within my head tag.