setup.php

<?php

    /* Config required to replace the database strings */
    require('config/config.php');

    /* HTML Form to be echoed for the user */
    $form = "
        <form name='form' action='' method='get'>
        <input type='text' name='host' placeholder='Database host' />
        <input type='text' name='database' placeholder='Database name' />
        <input type='text' name='username' placeholder='Database username' />
        <input type='password' name='password' placeholder='Database password' />
        <input type='submit' name='submit' value='Change values' />
        </form>
        ";
    /* Echo the form so I can see it */
    echo $form;
    /* Get the results from the HTML Form */
    $gethost = $_GET['host'];
    $getdb = $_GET['database'];
    $getuser = $_GET['username'];
    $getpass = $_GET['password'];
    /* Replace the database connections in config.php */
    /* However, does not work :/ */
    if (isset($_GET['submit'])) {
        str_replace($gethost,$host);
    }
?>