Fix viewport in hub page

src/hub.html

@@ -5,6 +5,8 @@
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <meta http-equiv="origin-trial" data-feature="WebVR (For Chrome M62+)" data-expires="<%= ORIGIN_TRIAL_EXPIRES %>" content="<%= ORIGIN_TRIAL_TOKEN %>">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
+
     <link rel="shortcut icon" type="image/png" href="/favicon.ico"/>
     <title>A new way to get together online | Hubs by Mozilla</title>
     <link href="https://fonts.googleapis.com/css?family=Zilla+Slab:300,300i,400,400i,700" rel="stylesheet">