Making things work again

In this pull request, there are three things:

1.) It was a total surprise to see the tool force me to specify a user but actually using the email for authentication. Plus it didn't work for me, so I changed that bit
2.) The Github API (now?) require a User-Agent header to be set. I added that as well.
3.) Chaning into the repository's directory does only work *after* cloning the repository into the backup directory. Don't go there before cloning, it screws up.