How I should use Object from contenttypes.yaml?

[AndreyChursin]

I read documentation and no information how I can use Entity from contenttypes.yaml ... of course my symfony experience not so good, but therefore:

1. I described entity News in contenttypes.yaml
2. I create App\Entity\News with php bin/console entity:create News
3. In controller try to create Object and save it:

$entityManager = $this->container->get('doctrine')->getManager();
$entity = new \App\Entity\News();
$entity->set('xml_id', rand());
...
$entityManager->persist($entity);
$entityManager->flush();

but got error:

An exception occurred while executing 'INSERT INTO bolt_news (title, content, published_at, xml_id) VALUES (?, ?, ?, ?)':
SQLSTATE[HY000]: General error: 1 no such table: bolt_news

So how programmatically use Entity from contenttypes.yaml