update meta tags

server/templates/instances.html.j2

@@ -3,6 +3,9 @@
 <html lang="en" data-bs-theme="dark">
   <head>
     <meta charset="utf-8">
+    <meta name="keywords" content="nitter, status, uptime" />
+    <meta name="description" content="Nitter instance uptime and status tracker." />
+    <meta name="author" content="" />
     <link href="/static/bootstrap.min.css" rel="stylesheet">
     <style>
     .uptime-graph rect {
@@ -160,4 +163,4 @@
       <script src="/static/sortable.min.js"></script>
       <script src="/static/table_toggle.js"></script>
   </body>
-</html>
+</html>