title: Chart.js v2 FillColor Vs BackgroundColor
body: <p>I am trying to draw a  line chart with using Chart.js version 2, as i undrestood in this version we dont have 
  fillColor property anymore and instead of it we should use backgroundColor,
  I have 2 different datasets and i want to fill them with different color also i want to set opacity to 0.</p>
  
  <pre><code>     datasets: [ {
                      label: "This Year",
                      backgroundColor: "rgba(225, 236, 240, 1)",
                      pointBackgroundColor: "rgba(107,200,213,1)",
                      data: [1200,800,300,460,500]
                  },
                  {
                      label: "Next Year",
                      backgroundColor: "rgba(83,132,153,1)",
                      pointBackgroundColor: "rgba(184, 0, 36, 1)",
                      data: [200,500,1300,610,320]
                   }
          ]};
  </code></pre>
  
  <p>the issue that i've faced is some parts of   "Next Year" 's wave and it's data points will be hide behind "This Year" wave.
  with fillColor in the previuse version we dont have this issue i guess, 
  could you please guid me how can i solve this problem? ......</p>