add stats and copyright

public/index.html

@@ -24,5 +24,14 @@
         if(/Android|iPhone|iPad|iPod/.test(navigator.userAgent))
             alert('你为什么不用 PKU Helper 客户端呢？');
     </script>
+    <script>
+        var cnzz_s_tag = document.createElement('script');
+        cnzz_s_tag.type = 'text/javascript';
+        cnzz_s_tag.async = true;
+        cnzz_s_tag.charset = "utf-8";
+        cnzz_s_tag.src = "https://w.cnzz.com/c.php?id=1274501752&async=1";
+        var root_s = document.getElementsByTagName('script')[0];
+        root_s.parentNode.insertBefore(cnzz_s_tag, root_s);
+    </script>
 </body>
 </html>