public function addBuilder(BuilderInterface $builder)
    {
        parent::addBuilder($builder);

        $builder->setVariables(
            $this->mergeParameters(
                $this->getFromYaml('params', array()),
                $this->getFromYaml(sprintf('builders.%s.params', $builder->getYamlKey()), array())
            )
        );
        $builder->setColumnClass($this->getColumnClass());
    }