add nginx stats

           # XXX: wtf vs http_requests_total

           prom_query(args, 'sum(rate(apache_accesses_total[30d]))')))

    print(" * number of nginx servers: %d, hits per second: %d, hit ratio: %0.2f" %  # noqa: E501

          (prom_query(args, 'count(count(nginx_http_request_details_total) by (alias))'),  # noqa: E501

           prom_query(args, 'sum(rate(nginx_http_request_details_total[30d]))'),  # noqa: E501

           prom_query(args, 'sum(nginx_http_request_details_total{upstream_cache_status="HIT"})/sum(nginx_http_request_details_total)'),  # noqa: E501

          ))

    print(" * number of self-hosted nameservers: %d, mail servers: %d" %

          (prom_query(args, 'sum(bind_up)'),

           prom_query(args, 'sum(postfix_up)')))