Пишем плагин для XF, который записывает в другую таблицу одобренные регистрации 2.1.0

<?php

namespace MMO\ApproveRegistration;

use XF\AddOn\AbstractSetup;
use XF\AddOn\StepRunnerInstallTrait;
use XF\AddOn\StepRunnerUninstallTrait;
use XF\AddOn\StepRunnerUpgradeTrait;
use XF\Db\Schema\Create;

class Setup extends AbstractSetup
{
   use StepRunnerInstallTrait;
   use StepRunnerUpgradeTrait;
   use StepRunnerUninstallTrait;

    public function installStep1()
    {
        $this->schemaManager()->createTable('xf_mar_approve_registration', function(Create $table) {
            $table->checkExists(true);
            $table->addColumn('id', 'int')->autoIncrement();
            $table->addColumn('user_id', 'int')->unsigned();
            $table->addColumn('username', 'varchar', 50);
            $table->addColumn('email', 'varchar', 120);
            $table->addColumn('is_active', 'tinyint', 3)->setDefault(0);
            $table->addPrimaryKey('id');
            $table->addKey('email');
        });
    }

    public function uninstallStep1()
    {
        $this->schemaManager()->dropTable('xf_mar_approve_registration');
    }
}

<?php

namespace MMO\ApproveRegistration\XF\Entity;

class User extends XFCP_User
{
    protected function _postSave()
    {
        if ($this->isStateChanged('user_state', 'moderated') && $this->user_state == 'valid')
        {
            /** @var \MMO\ApproveRegistration\XF\Entity\ApproveRegistration $approveUser */
            $approveUser = $this->_em->create('MMO\ApproveRegistration:ApproveRegistration');
            $approveUser->user_id = $this->user_id;
            $approveUser->username = $this->username;
            $approveUser->email = $this->email;
            $approveUser->is_active = true;
            $approveUser->save();
        }

        return parent::_postSave();
    }
}

<?php

namespace MMO\ApproveRegistration\Entity;

use XF\Mvc\Entity\Entity;
use XF\Mvc\Entity\Structure;

class ApproveRegistration extends Entity
{
    public static function getStructure(Structure $structure)
    {
        $structure->table = 'xf_mar_approve_registration';
        $structure->shortName = 'MMO\ApproveRegistration:ApproveRegistration';
        $structure->primaryKey = 'id';
        $structure->columns = [
            'id' => ['type' => self::UINT, 'autoIncrement' => true],
            'user_id' => ['type' => self::UINT, 'default' => 0],
            'username' => ['type' => self::STR, 'maxLength' => 50],
            'email' => ['type' => self::STR, 'maxLength' => 120],
            'is_active' => ['type' => self::BOOL, 'default' => true]
        ];
        $structure->relations = [
            'User' => [
                'entity' => 'XF:User',
                'type' => self::TO_ONE,
                'conditions' => 'user_id',
                'primary' => true
            ]
        ];
        return $structure;
    }