Fix #205: add flatJSON extension.

src/extensions/flatJSON/README.md

@@ -0,0 +1,17 @@
+# Table flatJSON
+
+Use Plugin: [bootstrap-table-flatJSON](https://github.com/djhvscf/bootstrap-table-flatJSON)
+
+## Usage
+
+```html
+<script src="extensions/flatJSON/bootstrap-table-flatJSON.js"></script>
+```
+
+## Options
+
+### flat
+
+* type: Boolean
+* description: Set true to flat the JSON object.
+* default: `false`