delete index_php and add new file

index_php.php

-<?php
-  if(isset($_POST['logout'])) {
-    session_name($user);
-    session_destroy();
-    header('Location: login_page.php');
-    exit;
-  }
-
-  if(isset($_POST['add-button'])){
-    $addTask = $_POST['add-task'];
-    $file = fopen("taskList.txt","a+") or die("Unable to open file");
-    $s = $addTask."\r\n";
-    fputs($file,$s) or die("Unable to open save");
-    fclose($file);
-    header('Location: index.php');
-  }
-
-?>