write mock json and generate baseline with docker

Author: satotake

test/image/baselines/axislabel_separatethousands.png

@@ -0,0 +1,15 @@
+{
+    "data": [
+        {
+            "x": [1000, 2000, 3000, 4000],
+            "y": [1000, 1500, 2000, 10000],
+            "type": "scatter"
+        }
+    ],
+    "layout": {
+        "yaxis": {
+            "exponentformat": "none", 
+            "separatethousands": true 
+        }
+    }
+}