Add webpacker and use it for new_design

app/javascript/new_design/toggle-chart.js

@@ -0,0 +1,28 @@
+import Chartkick from 'chartkick';
+
+export function toggleChart(event, chartClass) {
+  const nextSelectorItem = $(event.target),
+    nextChart = $(chartClass),
+    nextChartId = nextChart
+      .children()
+      .first()
+      .attr('id'),
+    currentSelectorItem = nextSelectorItem
+      .parent()
+      .find('.segmented-control-item-active'),
+    currentChart = nextSelectorItem
+      .parent()
+      .parent()
+      .find('.chart:not(.hidden)');
+
+  // Change the current selector and the next selector states
+  currentSelectorItem.toggleClass('segmented-control-item-active');
+  nextSelectorItem.toggleClass('segmented-control-item-active');
+
+  // Hide the currently shown chart and show the new one
+  currentChart.toggleClass('hidden');
+  nextChart.toggleClass('hidden');
+
+  // Reflow needed, see https://github.com/highcharts/highcharts/issues/1979
+  Chartkick.charts[nextChartId].getChartObject().reflow();
+}