🎨 Don't use header() to redirect to /login

Signed-off-by: Luke Tainton <luke@tainton.uk>

app/includes/header.php

@@ -8,6 +8,11 @@
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
     <meta name="theme-color" content="#563d7c">
+    <?php
+      if (!is_logged_in()) {
+        echo("<meta http-equiv='refresh' content='0; url=" . $_ENV['APP_URL'] . "/login' />");
+      }
+    ?>
     <title><?php echo( $PAGE_TITLE ); ?></title>
 
     <!-- Bootstrap core CSS -->