add example README.md

example/README.md

 
+# node-apollo-example
+
+  携程Apollo配置中心node SDK Docker example.
+
+## Usage
+* 适用框架:
+  * [eggjs](https://github.com/eggjs/egg)
+  * [thinkjs](https://github.com/thinkjs/thinkjs)
+  
+* 解决[#1394](https://github.com/eggjs/egg/issues/1394)
+
+## License
+
+[MIT](LICENSE)
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