Sample grouped bar chart made with d3.chart

Sample grouped bar chart made with d3.chart. Usage:

var groupedBarData = [
  {category: 'sam', val1: 10, val2: 13, val3: 5},
  {category: 'jenna', val1: 20, val2: 11, val3: 15},
  {category: 'peter', val1: 11, val2: 13, val3: 9},
];
var groupedBarChart = d3.select("#grouped-bar-chart")
  .append("svg")
  .chart("GroupedBarChart")
  .width(200)
  .height(150)
  ;
groupedBarChart.draw(groupedBarData);