public function post()
 {
     $user_name = $_POST['user_name'];
     $user_email = $_POST['user_email'];
     $thread_topic = $_POST['thread_topic'];
     $thread_content = $_POST['thread_content'];
     Thread::post($user_name, $user_email, $thread_topic, $thread_content);
     header("Location: index.php");
 }