public function addEntityReflection(EntityReflectionInterface $entityReflection)
    {
        // At the moment slug is not configurable otherwise
        $slug = $entityReflection->getSlug();

        if (isset($this->entitiesBySlug[$slug])) {
            throw new DomainErrorException('Two entities are registered with the same "'.$slug.'" slug!');
        }

        $this->entitiesBySlug[$slug] = $entityReflection;
    }