Update LaravelReadme.md

Author: mouyong

LaravelReadme.md

@@ -91,4 +91,36 @@ class Handler extends ExceptionHandler
 
 ```
 
-**注意：头请求未声明此次请求需要返回 json 数据时，`$this->fail($message, $err_code)` 的错误码需要符合 http status_code 响应码**
+## 控制器调用
+
+```
+<?php
+
+namespace App\Http\Controllers;
+
+use Illuminate\Http\Request;
+
+class DemoController extends Controller
+{
+    public function index()
+    {
+        // validate data
+        \validator()->validate(\request(), [
+            'name' => 'required|string',
+            'age' => 'nullable|integer',
+        ]);
+
+        // your business logic
+        $error = false;
+        if ($error) { // here business logic error.
+            throw new \RuntimeException('error message');
+        }
+
+        return $this->success([ // here response success
+            'key1' => 'value1',
+            'key2' => 'value2',
+        ]);
+    }
+}
+
+```