Including Licensed files into repository


I haven’t found an answer to my question so far, only how to license the whole repository. Right now I am doing a little unity project but I would like the code, so the main reason for a repo, to be free. But I don’t want to loose my rights on my assets that I made. So if I am working with someone do I need to give them the assets seperatelly or can I do it over the repository. Or would it even be a bad idea to give it over the repository giving that with bigger projects the files can become quite big.