Problems setting up ssh passthrough

Hi all,

I’ve setup gitea with docker and nginx and I want to access the repositories trough SSH on port 22. I found the section in the manual which covers this (https://docs.gitea.io/en-us/install-with-docker/#ssh-container-passthrough) but I’m not sure about where i want to place the file /app/gitea/gitea. There is no such directory called “app” created when I start the gitea via docker-compose.
In addition it says I should create a git user, but what if there is already a git user with no home directory?
I hope someone can help me out.