Add link to replit run (#379)

.replit

@@ -0,0 +1,2 @@
+language = "nodejs"
+run = "cd examples && node rainbow"

readme.md

@@ -9,7 +9,7 @@
 
 > Terminal string styling done right
 
-[![Build Status](https://travis-ci.org/chalk/chalk.svg?branch=master)](https://travis-ci.org/chalk/chalk) [![Coverage Status](https://coveralls.io/repos/github/chalk/chalk/badge.svg?branch=master)](https://coveralls.io/github/chalk/chalk?branch=master) [![npm dependents](https://badgen.net/npm/dependents/chalk)](https://www.npmjs.com/package/chalk?activeTab=dependents) [![Downloads](https://badgen.net/npm/dt/chalk)](https://www.npmjs.com/package/chalk) [![](https://img.shields.io/badge/unicorn-approved-ff69b4.svg)](https://www.youtube.com/watch?v=9auOCbH5Ns4) [![XO code style](https://img.shields.io/badge/code_style-XO-5ed9c7.svg)](https://github.com/xojs/xo) ![TypeScript-ready](https://img.shields.io/npm/types/chalk.svg)
+[![Build Status](https://travis-ci.org/chalk/chalk.svg?branch=master)](https://travis-ci.org/chalk/chalk) [![Coverage Status](https://coveralls.io/repos/github/chalk/chalk/badge.svg?branch=master)](https://coveralls.io/github/chalk/chalk?branch=master) [![npm dependents](https://badgen.net/npm/dependents/chalk)](https://www.npmjs.com/package/chalk?activeTab=dependents) [![Downloads](https://badgen.net/npm/dt/chalk)](https://www.npmjs.com/package/chalk) [![](https://img.shields.io/badge/unicorn-approved-ff69b4.svg)](https://www.youtube.com/watch?v=9auOCbH5Ns4) [![XO code style](https://img.shields.io/badge/code_style-XO-5ed9c7.svg)](https://github.com/xojs/xo) ![TypeScript-ready](https://img.shields.io/npm/types/chalk.svg) [![run on repl.it](http://repl.it/badge/github/chalk/chalk)](https://repl.it/github/chalk/chalk)
 
 <img src="https://cdn.jsdelivr.net/gh/chalk/ansi-styles@8261697c95bf34b6c7767e2cbe9941a851d59385/screenshot.svg" width="900">