fix structure product categories table and crud product

app/Models/ProductCategory.php

@@ -10,9 +10,17 @@ class ProductCategory extends Model
 {
     use HasFactory, SoftDeletes;
 
-    protected $fillable = ['name'];
+    protected $fillable = ['name','parent_id'];
 
     public function products(){
         return $this->hasMany(Product::class, 'product_category_id');
     }
+
+    public function parent(){
+        return $this->belongsTo(ProductCategory::class, 'parent_id');
+    }
+
+    public function children(){
+        return $this->hasMany(ProductCategory::class,'parent_id');
+    }
 }