Untitled

<?php

include __DIR__ . '/guestbook.php';

$guestbook = new GuestBook( __DIR__ . '/reviews.txt');

$guestbook->showbook();

?>

  <html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; meta charset="utf-8">
    </head>
    <body>

    <form name="test" method="post" action="/addReview.php">
        <p><input type="text" name="review"> <input type="submit" value="Оставить отзыв"></p>
    </form>

    </body>
    </html>