Update README.md

Tinywan · web-flow · commit 76b64beca065 · 2021-06-30T09:56:57.000+08:00
diff --git a/README.md b/README.md
@@ -25,6 +25,10 @@ Check out our other projects at [linkorb.com/engineering](http://www.linkorb.com
 
 Btw, we're hiring!
 
+## Installation
+```shell
+composer require linkorb/etcd-php
+```
 
 ## Usage
 
