fix(readme): Add usage documentation and badges

README.md

@@ -1,12 +1,28 @@
-# semantic-release-error
+# @semantic-release/error
 
+Error type used by all [semantic-release](https://github.com/semantic-release/semantic-release) packages.
+
+[![npm](https://img.shields.io/npm/v/@semantic-release/error.svg)](https://www.npmjs.com/package/@semantic-release/error)
 [![Greenkeeper badge](https://badges.greenkeeper.io/semantic-release/error.svg)](https://greenkeeper.io/)
-[![npm version](https://badge.fury.io/js/semantic-release-error.svg)](http://badge.fury.io/js/semantic-release-error)
-[![Build Status](https://travis-ci.org/semantic-release/error.svg?branch=master)](https://travis-ci.org/semantic-release/error)
-[![Dependency Status](https://david-dm.org/semantic-release/error.svg)](https://david-dm.org/semantic-release/error)
-[![devDependency Status](https://david-dm.org/semantic-release/error/dev-status.svg)](https://david-dm.org/semantic-release/error#info=devDependencies)
 [![license](https://img.shields.io/github/license/semantic-release/error.svg)](https://github.com/semantic-release/error/blob/master/LICENSE)
 [![styled with prettier](https://img.shields.io/badge/styled_with-prettier-ff69b4.svg)](https://github.com/prettier/prettier)
+[![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)
 [![Commitizen friendly](https://img.shields.io/badge/commitizen-friendly-brightgreen.svg)](http://commitizen.github.io/cz-cli/)
+
+[![Travis](https://img.shields.io/travis/semantic-release/error.svg)](https://travis-ci.org/semantic-release/error)
 [![Codecov](https://img.shields.io/codecov/c/github/semantic-release/error.svg)](https://codecov.io/gh/semantic-release/error)
 
+## Usage
+
+```js
+const SemanticReleaseError = require('@semantic-release/error');
+
+// Default
+throw new SemanticReleaseError();
+
+// With error message
+throw new SemanticReleaseError('An error happened');
+
+// With error message and error code
+throw new SemanticReleaseError('An error happened', 'ECODE');
+```