title: Extending Line Chart with custom line
body: <p>I'm trying to extend the Line chart in Chart.js with this code:</p>
  
  <pre><code>var shotsData = {
    labels: ["Shot 1", "Shot 2", "Shot 3", "Shot 4", "Shot 5"],
    datasets: [{ data: [5, 7, 1, 4, 9] }]
  };
  
  var ctx = document.getElementById("shots").getContext("2d");
  
  Chart.types.Line.extend({
      name: "LineAlt",
      initialize: function () {
          this.chart.ctx.beginPath();
          this.chart.ctx.moveTo(0, 15);
          this.chart.ctx.lineTo(159, 274);
          this.chart.ctx.stroke();
  
          Chart.types.Line.prototype.initialize.apply(this, arguments);
      }
  });
  
  new Chart(ctx).LineAlt(shotsData);
  </code></pre>
  
  <p>This draws my chart, but I also want a custom line within the chart, which is written inside the <code>initialize</code> function, but this seems to not work. When I remove the line <code>Chart.types.Line.prototype.initialize.apply(this, arguments);</code> the custom line is displayed.</p>
  
  <p>Here's a fiddle</p>
  
  <p><a href="http://jsfiddle.net/92ANv/5/" rel="nofollow">http://jsfiddle.net/92ANv/5/</a></p>