Deploy Symfony with Capistrano in Docker container

Normally I’m developping Symfony applications with Docker and deploy them with Capistrano to a server. I would also like to use Docker in production, but I can not figure out how to make the deploy with Capistrano. I only found this tutorial (https://www.goetas.com/blog/how-do-i-deploy-my-symfony-api-part-1-development/) but it’s to complex for what I really need.

SSH keys?
Configure Capistrano inside de Docker container?

Thanks!

Source: StackOverflow