defer conn.Close()
	tx.Statement.ConnPool = conn
	return fc(tx)
}

// Transaction start a transaction as a block, return error will rollback, otherwise to commit. Transaction executes an
// arbitrary number of commands in fc within a transaction. On success the changes are committed; if an error occurs
// they are rolled back.
func (db *DB) Transaction(fc func(tx *DB) error, opts ...*sql.TxOptions) (err error) {
	panicked := true

	DB.Migrator().DropTable(&Token{}, &TokenOwner{})
	DB.AutoMigrate(&Token{}, &TokenOwner{})

	saveTokenOwner := func(owner *TokenOwner) (*TokenOwner, error) {
		var newOwner TokenOwner
		if err := DB.Transaction(func(tx *gorm.DB) error {
			if err := tx.Session(&gorm.Session{FullSaveAssociations: true}).Save(owner).Error; err != nil {
				return err
			}