update README with new package structure

Author: Jake Teton-Landis

packages/eslint-config-airbnb/README.md

@@ -4,9 +4,26 @@ This package provides Airbnb's .eslintrc as an extensible shared config.
 
 ## Usage
 
+### With React Style
+
 1. `npm install --save-dev eslint-config-airbnb babel-eslint eslint-plugin-react`
-2. add `"extends": "eslint-config-airbnb"` to your .eslintrc
+2. add `"extends": "airbnb"` to your .eslintrc
+
+### Without React Style
+
+1. `npm install --save-dev eslint-config-airbnb babel-eslint `
+2. add `"extends": "airbnb/base"` to your .eslintrc
 
 See [Airbnb's Javascript styleguide](https://github.com/airbnb/javascript) and
 the [ESlint config docs](http://eslint.org/docs/user-guide/configuring#extending-configuration-files)
 for more information.
+
+## Improving this config
+
+Consider adding test cases if you're making complicated rules changes, like
+anything involving regexes. Perhaps in a distant future, we could use literate
+programming to structure our README as test cases for our .eslintrc?
+
+You can run tests with `npm test`.
+
+You can make sure this module lints with itself using `npm run lint`.