Change histogram color to Grey and make background white

Author: William Lai

src/charts/Histogram.java

@@ -47,7 +47,10 @@ private static JFreeChart createChart(IntervalXYDataset dataset) throws IOExcept
         );
         XYPlot plot = (XYPlot) chart.getPlot();
         //Set Histogram Color to Red
-        plot.getRenderer().setSeriesPaint(0, Color.red);
+        plot.getRenderer().setSeriesPaint(0, new Color(51, 51, 51));
+        plot.setBackgroundPaint(Color.white);
+        plot.setRangeGridlinePaint(Color.black);
+        plot.setDomainGridlinePaint(Color.black);
 
         //Turn off Glossy 3D on bar chart
         XYBarRenderer renderer = (XYBarRenderer) plot.getRenderer();