DoctrineExtensions: Sluggable

Wouldn't a better practice be to append genus-id rather than adding a new column to the database?

Hello,
I'm trying to start that code on symfony 4, but I got this error:

Cannot autowire service "App\Service\MarkdownTransformer": argument "$cache" of method "__construct()" references interface "Doctrine\Common\Cache\Cache" but no such service exists. You should maybe
alias this interface to one of these existing services: "annotations.filesystem_cache", "annotations.cache", "doctrine_cache.providers.doctrine.orm.default_metadata_cache", "doctrine_cache.provider
s.doctrine.orm.default_result_cache", "doctrine_cache.providers.doctrine.orm.default_query_cache".

Does anybody know what to do?

Is there anything inherently wrong in this code. I ask because after running for 18 hours it has set 20 SLUGS..... Note I use the unit of work as setting slug to null wouldnt trigger persistance as it defaults to null.

class Version20170723121131 extends AbstractMigration implements ContainerAwareInterface
{

    use ContainerAwareTrait;

    /**
     * @param Schema $schema
     */
    public function up(Schema $schema)
    {
        // this up() migration is auto-generated, please modify it to your needs
        $this->abortIf($this->connection->getDatabasePlatform()->getName() !== 'mysql', 'Migration can only be executed safely on \'mysql\'.');

        $this->addSql('ALTER TABLE person ADD slug VARCHAR(255) DEFAULT NULL');
        $this->addSql('CREATE UNIQUE INDEX UNIQ_34DCD176989D9B62 ON person (slug)');

    }

    public function postUp(Schema $schema)
    {
        $em = $this->container->get("doctrine.orm.entity_manager");

        $people = $em->getRepository(Person::class)->findAll();

        foreach ($people as $person) {
            $uow = $em->getUnitOfWork();
            $uow->propertyChanged($person, 'slug', NULL, NULL);
            $uow->scheduleForUpdate($person);
            $em->flush();
        }

        parent::postUp($schema); // TODO: Change the autogenerated stub

    }

    /**
     * @param Schema $schema
     */
    public function down(Schema $schema)
    {
        // this down() migration is auto-generated, please modify it to your needs
        $this->abortIf($this->connection->getDatabasePlatform()->getName() !== 'mysql', 'Migration can only be executed safely on \'mysql\'.');
        $this->addSql('ALTER TABLE person DROP slug');
    }

    /**
     * Sets the container.
     *
     * @param ContainerInterface|null $container A ContainerInterface instance or null
     */
    public function setContainer(ContainerInterface $container = null)
    {
        $this->container = $container;
    }
}

This would not work for me until I set "nullable=true" on the $slug field in Genus entity. Since it wasn't working I was just going to allow it to be null and then manually fix things just to keep going. Once I did so then all worked without further manual intervention. Strange!

Hey guys,
I dont understand why I can't install the stof bundle since I started with the course code. This is what I get from the terminal :
- Installation request for symfony/symfony (locked at v3.1.4, required as 3.1.*) -> satisfiable by symfony/symfony[v3.1.4].
Any clue?
thx