add appveyor ci badge

README.md

 ![Wechaty](https://raw.githubusercontent.com/zixia/wechaty/master/image/wechaty-logo-en.png)
-# Wechaty [![Circle CI](https://circleci.com/gh/zixia/wechaty.svg?style=svg)](https://circleci.com/gh/zixia/wechaty) [![Build Status](https://travis-ci.org/zixia/wechaty.svg?branch=master)](https://travis-ci.org/zixia/wechaty)
+# Wechaty [![Circle CI](https://circleci.com/gh/zixia/wechaty.svg?style=svg)](https://circleci.com/gh/zixia/wechaty) [![Build Status](https://travis-ci.org/zixia/wechaty.svg?branch=master)](https://travis-ci.org/zixia/wechaty) [![Build status](https://ci.appveyor.com/api/projects/status/60fgkemki7e6upb9?svg=true)](https://ci.appveyor.com/project/zixia/wechaty)
+
 Wechaty is a Chatbot Library for Wechat **Personal** Account.
 
 > Easy creating personal account wechat robot in 10 lines of code.

appveyor.yml

+# http://www.appveyor.com/docs/appveyor-yml
+
+# Test against these versions of Io.js and Node.js.
+environment:
+  matrix:
+  # node.js
+    - nodejs_version: "0.8"
+    - nodejs_version: "0.10"
+    - nodejs_version: "0.12"
+    - nodejs_version: "4"
+    - nodejs_version: "5"
+    - nodejs_version: "6"
+
+# Install scripts. (runs after repo cloning)
+install:
+  # Get the latest stable version of Node.js or io.js
+  - ps: Install-Product node $env:nodejs_version
+  # install modules
+  - npm install
+
+# Post-install test scripts.
+test_script:
+  # Output useful info for debugging.
+  - node --version
+  - npm --version
+  # run tests
+  - npm test
+
+# Don't actually build.
+build: off
+
+# Set build version format here instead of in the admin panel.
+version: "{build}"