How can I share redis/postgress service with other docker containers

[GuyKh]

I'm interested in reusing redis for ntopng (https://hub.docker.com/r/vimagick/ntopng)

As you can see - it also uses redis.
How can I share the redis container for both?

[bo0tzz]

Why? Redis is incredibly lightweight, just spin up another container and avoid any chance of conflict