Add example

README.md

@@ -1,7 +1,27 @@
 # bpe-tokeniser
 
-![PHP Test](https://github.com/danny50610/bpe-tokeniser/actions/workflows/php.yml/badge.svg)
+[![PHP Test](https://github.com/danny50610/bpe-tokeniser/actions/workflows/php.yml/badge.svg)](https://github.com/danny50610/php-cid/actions)
 [![codecov](https://codecov.io/gh/danny50610/bpe-tokeniser/graph/badge.svg?token=CGORRQ1P6W)](https://codecov.io/gh/danny50610/bpe-tokeniser)
+[![Latest Stable Version](http://poser.pugx.org/danny50610/php-cid/v)](https://packagist.org/packages/danny50610/php-cid)
+[![Total Downloads](http://poser.pugx.org/danny50610/php-cid/downloads)](https://packagist.org/packages/danny50610/php-cid)
 
 PHP port for [openai/tiktoken](https://github.com/openai/tiktoken) (most)
 
+## Installation
+
+```sh
+composer require danny50610/bpe-tokeniser
+```
+
+## Example
+
+### GPT-4 / GPT-3.5-Turbo (cl100k_base)
+```php
+<?php
+use Danny50610\BpeTokeniser\EncodingFactory;
+
+$enc = EncodingFactory::createByEncodingName('cl100k_base');
+
+var_dump($enc->decode($enc->encode("hello world")));
+// output: string(11) "hello world"
+```