Fixes #1195 Made the charts responsive for small screens

app/views/admin/conferences/_doughnut_chart.html.haml

@@ -1,6 +1,23 @@
 .text-center
   %h4 #{title}
-  %canvas.doughnut_chart{ 'data-chart' => data.to_json }
+  %canvas.doughnut_chart{ id: "dough_#{title}", 'data-chart' => data.to_json }
 - if data
   - data.each do |key, value|
     %span{ 'style' => "border-bottom: 3px solid #{value['color']}" } #{key}: #{value['value']}
+
+:javascript
+  $(document).ready( function(){
+
+   var d = $("#dough_#{title}");
+   var dt = d.get(0).getContext('2d');
+
+   $(window).resize( respondCanvas );
+
+   function respondCanvas(){
+    dt.canvas.width = 150;
+    dt.canvas.height = 150;
+   }
+
+   respondCanvas();
+
+  });