title: How to change bar fillColor in chart.js bar char
body: <p>I use chart.js to draw a bar chart. How to change the bar fill color in chart.js.(I use the 'Bar chart' )</p>
  
  <pre><code>var data = {
  labels : ["January","February","March","April","May","June","July"],
  datasets : [
      {
          fillColor : "rgba(220,220,220,0.5)",
          strokeColor : "rgba(220,220,220,1)",
          data : [65,59,90,81,56,55,40]
      },
      {
          fillColor : "rgba(151,187,205,0.5)",
          strokeColor : "rgba(151,187,205,1)",
          data : [28,48,40,19,96,27,100]
      }
  ]
  </code></pre>
  
  <p>}</p>
  
  <p>What's the fillColor : "rgba(220, 220, 220, 0.5) mean? How can I change this color?</p>