优化网站列表渲染，填充预设网站

Author: hui-ho

app/Category.php

@@ -10,6 +10,11 @@ class Category extends Model
 {
     use ModelTree, AdminBuilder;
 
+    public function children()
+    {
+        return $this->hasMany(static::class, 'parent_id');
+    }
+
     public function sites()
     {
         return $this->hasMany(Site::class);

app/Http/Controllers/HomeController.php

@@ -10,8 +10,7 @@ class HomeController extends Controller
     public function index()
     {
         return view('index', [
-            'categories' => Category::getWithArray(),
-            'sites' => Category::where('parent_id', '<>', 0)->get(),
+            'categories' => Category::with('children', 'sites')->get(),
         ]);
     }
 }