Add install docs to the readme

README.md

@@ -2,6 +2,30 @@
 
 [![Build Status](https://travis-ci.org/mozilla/eslint-config-protocol.svg?branch=master)](https://travis-ci.org/mozilla/eslint-config-protocol)
 
-A shared ESLint config for [Protocol](https://github.com/mozilla/protocol/) related projects.
+A shared [ESLint](https://eslint.org/) config for [Protocol](https://github.com/mozilla/protocol/) related projects.
+
+## Installation
+
+```
+npm install @mozilla-protocol/eslint-config
+```
+
+## Configuration
+
+For browser environments, extend your `.eslintrc.js` config file with default rule set:
+
+```
+extends: "@mozilla-protocol/eslint-config"
+```
+
+For Node environments, extend the `index-node` rule set:
+
+```
+extends: "@mozilla-protocol/eslint-config/index-node"
+```
+
+
+
+