Add json file for sample

htdocs/data/c3_test.json

@@ -0,0 +1,5 @@
+{
+  "data1": [120, 140, 170, 150, 180],
+  "data2": [80, 50, 100, 70, 120],
+  "data3": [200, 210, 250, 300, 280]
+}