Add babelrc tip

src/dev/web/front/babel-preset-stage-2.md

@@ -0,0 +1,18 @@
+# Babel and babel-preset-stage-2
+
+If you want use the "Spead Operator" eg `...` in javascript, you need `babel-preset-stage-2`.
+
+```shell
+yarn add -D babel-preset-stage-2
+```
+
+Then enable it your babelrc :
+
+```javascript
+{
+    "presets": [
+        ["es2015", { "modules": false }],
+        ["stage-2"]
+    ]
+}
+```