Better structure

index.php

@@ -1,10 +1,10 @@
 <?php
-include_once 'database.php';
+include_once "errors.php";
+include_once "headers.php";
+Headers::json();
+include_once "database.php";
 
-ini_set(display_errors, 1);
-error_reporting(E_ALL);
-
-$db = openConnection();
+$db = DB::openConnection();
 
 $query = "SELECT * FROM users";
 
@@ -12,5 +12,6 @@ $stmt = $db->prepare($query);
 $stmt->execute();
 $result = $stmt->fetch(PDO::FETCH_ASSOC);
 
-echo json_encode($result);	
-?>
+DB::closeConnection($db);
+
+echo json_encode($result);