Entity/Menu.php
public function addChild(\Skillberto\SonataPageMenuBundle\Entity\Menu $children)
    {
        $this->children[] = $children;

        return $this;
    }
public function addChild(\Skillberto\SonataPageMenuBundle\Entity\Menu $children)
    {
        $this->children[] = $children;

        return $this;
    }
Add children

@param \Skillberto\SonataPageMenuBundle\Entity\Menu $children
@return Menu