🎉 Update readme.md

README.md

@@ -10,4 +10,46 @@
 [![Total Downloads](https://img.shields.io/packagist/dt/HavenShen/Slim-Cors.svg?style=flat-square)](https://packagist.org/packages/HavenShen/Slim-Cors)
 [![License](https://img.shields.io/packagist/l/HavenShen/Slim-Cors.svg?style=flat-square)](https://packagist.org/packages/HavenShen/Slim-Cors)
 
-This repository contains a Slim Framework CORS middleware.
+This repository contains a Slim Framework CORS middleware.
+
+## Install
+
+Via Composer
+
+``` bash
+$ composer require havenshen/slim-cors
+```
+
+Requires Slim 3.0.0 or newer.
+
+## Usage
+
+In most cases you want to register HavenShen\Slim\Cors.
+
+### Register
+
+```php
+$app = new \Slim\App([
+    'settings' => [
+        'dispayErrorDetails' => true,
+    ]
+]);
+
+$container = $app->getContainer();
+
+$container['cors'] = function ($c) {
+    return new \HavenShen\Slim\Cors\Guard;
+};
+
+$app->add($container->get('csrf'));
+```
+
+## Testing
+
+``` bash
+$ phpunit
+```
+
+## License
+
+The MIT License (MIT). Please see [License File](LICENSE.md) for more information.