feat: add user request validation

app/Http/Requests/UserRequest.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class UserRequest extends FormRequest
+{
+    /**
+     * Determine if the user is authorized to make this request.
+     *
+     * @return bool
+     */
+    public function authorize()
+    {
+        return true;
+    }
+
+    /**
+     * Get the validation rules that apply to the request.
+     *
+     * @return array<string, mixed>
+     */
+    public function rules()
+    {
+        return [
+            'username' => 'required|unique:users,username',
+            'email' => 'required|email|unique:users,email',
+            'password' => 'required',
+            'password_confirmation' => 'required|same:password',
+        ];
+    }
+}