Actually, you can commit from github. Go to any file and hit Edit at the top right. It's a single file editor, so don't expect much out of it, but it is conceiv

Actually, you can commit from github. Go to any file and hit Edit at the top right. It's a single file editor, so don't expect much out of it, but it is conceivable for someone to contribute without using git. And to your point, you cannot add files via github.