Push jar-file to gitlab maven packages for CI

  docker, gitlab, java, maven, repository

I am using maven to write a java program and i have a gitlab repository. Now i want CI to run my junit-tests. So i am creating a maven-docker and try to run them, but it fails because of a missing dependency. The dependency is not available in the docker.
The dependency is in my local maven repository because i added it. There only exists the jar-file and it is not available in a public repository (it is beautyeye-lnf). How can i push the jar-file to gitlab maven packages?
I have read the following article, but wasn’t successfull (i do not have a project, just the jar-file)

Is this possible? Or do i not understand the docs?

Source: Docker Questions