Redmine

Hello,

I have a docker-compose file used to deploy redmine:4.2 and a mysql db.
I am looking for a clean and permanent way to apply a patch to redmine in this context.

I have looked for documentation online but haven't found anything related to this issue.
Right now my only option seems to be building my own docker image based on the official one, install the "patch" package (not sure how, my tests on that matter have always failed until now), and apply my specific patch.
Am I missing something simple ?

Thanks.
Regards