adding analytics

docs/VaccineDistributionByZipcode.html

@@ -5,6 +5,15 @@
     <meta charset="utf-8" />
     <meta content="width=device-width, initial-scale=1.0" name="viewport" />
     <title>Pfizer Vaccine Distribution by ZIP Code</title>
+    <!-- Google tag (gtag.js) -->
+    <script async src="https://www.googletagmanager.com/gtag/js?id=G-ERHYDH4P64"></script>
+    <script>
+        window.dataLayer = window.dataLayer || [];
+        function gtag() { dataLayer.push(arguments); }
+        gtag('js', new Date());
+
+        gtag('config', 'G-ERHYDH4P64');
+    </script>
     <link href="https://cdn.datatables.net/1.13.1/css/jquery.dataTables.css" rel="stylesheet" type="text/css" />
     <link href="batchCodeTable.css" rel="stylesheet" type="text/css" />
     <link href="forkMeOnGitHub.css" rel="stylesheet" type="text/css" />