add documentation to README.md

README.md

@@ -1,2 +1,95 @@
 # cakephp-asset
+[![Build Status](https://travis-ci.org/frankfoerster/cakephp-asset.svg?branch=master)](https://travis-ci.org/frankfoerster/cakephp-asset)
+
 Provides a CakePHP 3.x AssetHelper to selectively add last modified timestamps to css and js assets.
+CakePHP's implementation of Asset timestamps does not allow you to apply the behavior selectively to single files. Therefore I created this little Helper.
+
+## Installation
+
+You can install this plugin into your CakePHP application using [composer](http://getcomposer.org).
+
+Run the following command
+```sh
+composer require frankfoerster/cakephp-asset
+ ```
+
+## Configuration
+
+You can load the plugin using the shell command:
+
+```
+bin/cake plugin load FrankFoerster/Asset
+```
+
+Or you can manually add the loading statement in the **config/boostrap.php** file of your application:
+
+```php
+Plugin::load('FrankFoerster/Asset');
+```
+
+## Load the Helper
+
+Load the AssetHelper in the **src/View/AppView.php** file of your application.
+
+```php
+...
+public function initialize()
+{
+    $this->loadHelper('Asset', [
+        'className' => 'FrankFoerster/Asset.Asset'
+    ]);
+}
+...
+```
+
+## Use the AssetHelper in your Layout.
+
+The last modified time of the asset files is automatically appended.
+
+The methods provided are ``AssetHelper::css()`` and ``AssetHelper::js()``. Both take up to three arguments:
+
+1. ``$path`` - The path to the asset relative to the webroot of your app or plugin.
+2. ``$plugin`` - Either false to link to an app asset, or the name of a plugin. (default false)
+3. ``$appendTimestamp`` - Whether to append a last modified timestamp to the url. (default true)
+
+### CSS
+
+Linking the CSS file **your_app/webroot/css/app.css**
+
+```php
+echo $this->Asset->css('css/app.css');
+```
+
+produces the following output:
+
+```html
+<link rel="stylesheet" type="text/css" href="css/app.css?t=1460443221">
+```
+
+### JS
+
+Linking the JS file **your_app/webroot/js/app.js**
+
+```php
+echo $this->Asset->js('js/app.js');
+```
+
+produces the following output:
+
+```html
+<script type="text/javascript" src="js/app.js?t=1460443221"></script>
+```
+
+### Linking Plugin Assets
+
+Linking the JS file **MyPluginRootPath/webroot/js/plugin.js**
+
+```php
+echo $this->Asset->js('js/plugin.js', 'MyPlugin');
+```
+
+produces the following output:
+
+```html
+<script type="text/javascript" src="my_plugin/js/plugin.js?t=1460443221"></script>
+```