@ebbe Well at least you know how to delete a repo and get a new one now 
So by making the new repo "merleyn/ww2_oil_and_snow_1st_edition" you know you have the latest triplea one and it'll allow others to Fork it and add changes to it for you. That way you can check them out before you push them to the main triplea-maps one. At least I think lol
So lets say someone forks your merleyn repo, the one you Forked from triplea-maps, you can check out their fork by hitting "Code" and "Download Zip" of their Fork. Then you can put that zip in your triplea downloaded maps folder and try it out.

When you want to add something to "tripleamaps/ww2_oil_and_snow_1st_edition " you need to clone it. The green Code button again. This is where I better stop for now. I don't know how to do it with the pull and drag method. Only by terminal.
If you Fork the repo and then I can do the same you'll be able to DL the zip and checkout the changes. If you like them I can do a PR for you. But I don't really know how else to do it. I guess i could send files to you via sendspace or something, but seems as if we shouldn't have to do that.
Hmm...this might work. I'll make the changes to my Fork of oil and snow and you can DL the zip from there and if you like them I'll do the PR. You should do a map.yaml update as well but not necessary right away. Basically I try to test add enough stuff that they don't spam out. This is a new map so you'll have a few things to tune up but we'll talk about the yaml later.
Eventually you'll do it is the goal. I'm obviously not the best teacher lol