feat : 테이블 및 DB 마이그레이션 파일 추가

products
  - common_codes
  - parts
  - products
  - files
  - price_histories
  - boms
  - bom_items

  boards
  - boards
  - board_settings
  - posts
  - board_comments
  - board_files
  - post_custom_field_values

  permissions
  - menus
  - roles
  - user_menu_permissions
  - role_menu_permissions

  tenants
  - tenants
  - plans
  - subscriptions
  - payments

app/Models/Products/CommonCode.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Models\Products;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class CommonCode extends Model
+{
+    use SoftDeletes;
+    protected $fillable = ['tenant_id','code_group','code','name','parent_id','description','is_active','sort_order'];
+
+    public function parent() {
+        return $this->belongsTo(self::class, 'parent_id');
+    }
+    public function children() {
+        return $this->hasMany(self::class, 'parent_id');
+    }
+}