I have been struggling a bit getting it to work to delegate some of my features to a private gitlab repo. I am not sure how I should configure it in my composer.json.
Seems like I'm messing something up with a token or ssh key. As far as I can tell it would be easiest with at token, when I am going to distribute the code to several servers?
It basically adds everything to an auth.json file in the ~/.composer directory. You only need to add this once on your server ;) If you use something like docker, it's recommended to use the command line version.