WIP: rating table demo with tabulator, group by and frozen columns #396

sandbox/ratingTable.html

 <link href="https://unpkg.com/tabulator-tables@4.2.3/dist/css/tabulator.min.css" rel="stylesheet">
 <script type="text/javascript" src="https://unpkg.com/tabulator-tables@4.2.3/dist/js/tabulator.min.js"></script>
 <div id="example-table"></div>
-<script type="text/javascript" src="table.js"></script>
+<script type="text/javascript" src="table.js" charset="utf-8"></script>