This example will help you enable Second Level Cache in Symfony with Redis, also there is an example for Doctrine Extensions Translatable and Doctrine Behaviours Translatable.
Libraries we need:
composer require doctrine/doctrine-bundle doctrine/orm snc/redis-bundle predis/predis
Hey @sterichards, this gist is from 6 years ago, something might have changed in between, haven't used 2nd level cache in a long time.