foreignKey method
Implementation
ColumnDefinition foreignKey(String referencesTable, String referencesColumn,
    {String onUpdate = 'CASCADE', String onDelete = 'CASCADE'}) {
  _foreignTable = referencesTable;
  _foreignColumn = referencesColumn;
  _onUpdate = onUpdate;
  _onDelete = onDelete;
  _schema.foreign(
    _name,
    _foreignTable!,
    _foreignColumn!,
    onUpdate: _onUpdate ?? 'CASCADE',
    onDelete: _onDelete ?? 'CASCADE',
  );
  return this;
}