Thanks! I've pushed the patch with the following modifications.

- I changed the commit message to conform to our conventions. (Hint: If
  you're using emacs, you can generate this commit message easily using
  the yasnippets provided under etc/snippets in the Guix source tree.
- I changed the source to use git-fetch. GitHub's autogenerated source
  tarballs are unstable, and we should prefer git-fetch in such
  cases. Notice that `guix lint' also warns of this.
- I added a copyright header for you.