Improve README, add travis config file

.travis.yml

@@ -0,0 +1,6 @@
+language: node_js
+node_js:
+  - "node"
+
+before_script:
+  - npm install

README.md

@@ -1,12 +1,18 @@
 # Vanity ETH
 
+[![Build Status](https://travis-ci.org/bokub/vanity-eth.svg?branch=master)](https://travis-ci.org/bokub/vanity-eth)
+[![Maintainability](https://api.codeclimate.com/v1/badges/818874f09ea56c310072/maintainability)](https://codeclimate.com/github/bokub/vanity-eth/maintainability)
+[![XO code style](https://img.shields.io/badge/code_style-XO-5ed9c7.svg)](https://github.com/sindresorhus/xo)
+
 Browser-based ETH vanity address generator
 
 Just type [`git.io/veth`](https://git.io/veth) to use it ⚡️
 
 ## Local usage
 
-If for any reason you don't want to use the version hosted by Github pages, download / clone the project and open `index.html` with your web browser
+If for any reason you don't want to use the version hosted by Github pages, download / clone the project and open `index.html` with your web browser.
+
+⚠ For some reason, some browsers such as chrome disallow multi-thread computation when run from a local file.
 
 ## Local development