src/Tomahawk/DependencyInjection/Container.php
public function tag($id, $tag)
    {
        if ( ! isset($this->serviceTags[$id])) {
            $this->serviceTags[$id] = [];
        }

        $this->serviceTags[$id][] = $tag;
        return $this;
    }
public function tag($id, $tag)
    {
        if ( ! isset($this->serviceTags[$id])) {
            $this->serviceTags[$id] = [];
        }

        $this->serviceTags[$id][] = $tag;
        return $this;
    }
Tag a service

@param string $id
@param string $tag
@return $this