Update readme

Author: snapshotpl

README.md

@@ -1,10 +1,35 @@
 # maintenance [![Build Status](https://travis-ci.org/php-middleware/maintenance.svg?branch=master)](https://travis-ci.org/php-middleware/maintenance)
 Site maintenance middleware SEO friendly
 
+## How to usage
+
+Create instance of middleware as you want (we use [named constructors](http://verraes.net/2014/06/named-constructors-in-php/)) and add it to middleware runner.
+
+```php
+$date = DateTime::createFromFormat('Y-m-d H:i:s', '2025-11-30 11:12:13');
+
+$middleware = MaintenanceMiddleware::createWithRetryAsDateTime($date);
+
+$middlewareRunner->add(middleware);
+$middlewareRunner->run();
+```
+
 ## Features
 
-* Setup 503 header,
-* Support `Retry-After` header (as seconds, or HTTP-date),
-* Support `Redirect` header (redirect page after `Retry-After` time).
+* Setup 503 status code,
+* Supports `Retry-After` header (as seconds or HTTP-date),
+* Supports `Redirect` header (redirect page after `Retry-After` time).
+
+More about this SEO practice: [How to deal with planned site downtime](http://googlewebmastercentral.blogspot.com/2011/01/how-to-deal-with-planned-site-downtime.html) in Google Webmaster Central Blog.
+
+## How to install
+
+Use composer!
 
-More about this SEO practice: [How to deal with planned site downtime](http://googlewebmastercentral.blogspot.com/2011/01/how-to-deal-with-planned-site-downtime.html) in Google Webmaster Central Blog.
+```json
+{
+    "require": {
+        "php-middleware/maintenance": "^1.0.0"
+    }
+}
+```