Update to require header.php instead of header.html

index.php

@@ -1,5 +1,5 @@
 <?php
-    require "header.html";
+    require "header.php";
 ?>
 <!-- Small boxes (Stat box) -->
 <div class="row">

list.php

@@ -1,6 +1,6 @@
 <?php
 session_start();
-require "header.html";
+require "header.php";
 
 $list = $_GET['l'];
 

queries.php

@@ -1,5 +1,5 @@
 <?php
-    require "header.html";
+    require "header.php";
 ?>
 
 <!--