doc: update usage example

Author: koshuang

README.md

@@ -1,7 +1,7 @@
 # laravel-log-enhancement
 
 [![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg?style=flat-square)](LICENSE.md)
-[![Travis](https://img.shields.io/travis/onramplab/laravel-log-enhancement.svg?style=flat-square)]()
+[![CircleCI](https://circleci.com/gh/OnrampLab/next-starter.svg?style=shield)]()
 [![Total Downloads](https://img.shields.io/packagist/dt/onramplab/laravel-log-enhancement.svg?style=flat-square)](https://packagist.org/packages/onramplab/laravel-log-enhancement)
 
 
@@ -14,7 +14,40 @@ composer require onramplab/laravel-log-enhancement
 
 ## Usage
 
-Write a few lines about the usage of this package.
+Use `LogWithClassPath` trait to let it automatically put class path into log context. You can refer to following code example.
+
+```php
+namespace App;
+
+use Onramplab\LaravelLogEnhancement\Concerns\LogWithClassPath;
+
+class Fake {
+  use LogWithClassPath;
+
+  public function run()
+  {
+    $this->info('Test');
+  }
+}
+```
+
+The log json will look like this:
+
+```json
+{
+  "message": "Test",
+  "context": {
+    "class_path": "App\\Fake"
+  },
+  "level": 200,
+  "level_name": "INFO",
+  "channel": "local",
+  "extra": {},
+  "timestamp": "2021-01-04T22:47:56.598608-0800"
+}
+```
+
+
 
 
 ## Testing