GoUsers: add Slovakia section with company links Change-Id: If9836d6ee1ce2a5b4c5ac920b4bf7a4f48b385f1 GitHub-Last-Rev: 92f45571f29b1b5feb5c4209614ea52a410ea951 GitHub-Pull-Request: golang/wiki#81 Reviewed-on: https://go-review.googlesource.com/c/wiki/+/736821 Reviewed-by: Sean Liao <sean@liao.dev>