How to deploy with docker compose file using an existing mongodb container?

[yoshua]

Hello, I found that many examples need start a new mongodb container when installing nodebb. However, I have installed mongodb in a container on my server. I have created a root user and root passward for the mongodb. But I haven't create a database. Then how to install nodebb in this case, what's should be modified in the docker compose file in order to run correctly? Thanks.