chore: add CI

Author: benjycui

.travis.yml

@@ -0,0 +1,6 @@
+language: node_js
+node_js:
+  - "4"
+  - "5"
+  - "6"
+  - "7"

README.md

@@ -1,5 +1,10 @@
 # dva-model-extend
 
+[![](https://img.shields.io/travis/dvajs/dva-model-extend.svg?style=flat-square)](https://travis-ci.org/dvajs/dva-model-extend)
+[![npm package](https://img.shields.io/npm/v/dva-model-extend.svg?style=flat-square)](https://www.npmjs.org/package/dva-model-extend)
+[![NPM downloads](http://img.shields.io/npm/dm/dva-model-extend.svg?style=flat-square)](https://npmjs.org/package/dva-model-extend)
+[![Dependency Status](https://david-dm.org/dvajs/dva-model-extend.svg?style=flat-square)](https://david-dm.org/dvajs/dva-model-extend)
+
 Utility method to extend dva model.
 
 ## Installation