Update Readme

Author: danakt

README.md

@@ -1,5 +1,8 @@
 # Node.js Etherscan API
 
+[![npm](https://img.shields.io/npm/v/node-etherscan-api.svg?style=flat-square)](https://www.npmjs.com/package/node-etherscan-api)
+[![Travis branch](https://img.shields.io/travis/danakt/node-etherscan-api/master.svg?style=flat-square)](https://travis-ci.org/danakt/node-etherscan-api)
+
 Node.js package to interact with official [Etherscan API](https://etherscan.io/apis)
 
 ## Install