Simple ExpressionEngine bootstrap (config) file

bootstrap.php

<?php defined('BASEPATH') OR exit('No direct script access allowed');

/*
 * Put this file in your ExpressionEngine root folder (next to index.php)
 */

/*
 * OPTIONS (ALL PATHS ARE RELATIVE TO THE CURRENT DIRECTORY)
 */

$bootstrap['images_dir'] = 'images';
$bootstrap['themes_dir'] = 'themes';
$bootstrap['templates_dir'] = 'templates';
$bootstrap['third_party_dir'] = 'third_party';
$bootstrap['cp_url'] = 'system/';
$bootstrap['save_templates_as_files'] = TRUE;

$db['expressionengine']['hostname'] = 'localhost';
$db['expressionengine']['username'] = '';
$db['expressionengine']['password'] = '';
$db['expressionengine']['database'] = '';

/*
 * DON'T EDIT BELOW THIS LINE
 */

if ( ! defined('BOOTSTRAP_BASE_URL'))
{
	if (empty($_SERVER['HTTPS']) OR strtolower($_SERVER['HTTPS']) == 'off')
	{
		define('BOOTSTRAP_BASE_URL', 'http://'.$_SERVER['HTTP_HOST'].'/');
	}
	else
	{
		define('BOOTSTRAP_BASE_URL', 'https://'.$_SERVER['HTTP_HOST'].'/');
	}

	define('BOOTSTRAP_BASE_PATH', realpath(dirname(__FILE__)).DIRECTORY_SEPARATOR);

	/**
	 * Find the actual path from a relative path
	 */
	function bootstrap_build_path($path)
	{
		if (($realpath = realpath(BOOTSTRAP_BASE_PATH.$path)) === FALSE)
		{
			exit(BOOTSTRAP_BASE_PATH.$path.' does not exist!');
		}

		return $realpath.DIRECTORY_SEPARATOR;
	}

	/**
	 * Prefix base url, and remove double slashes
	 */
	function bootstrap_build_url($url)
	{
		return preg_replace("#(^|[^:])//+#", "\\1/", BOOTSTRAP_BASE_URL.$url.'/');
	}
}

$config['site_url'] = BOOTSTRAP_BASE_URL;
$config['base_url'] = BOOTSTRAP_BASE_URL;
$config['cp_url'] = bootstrap_build_url($bootstrap['cp_url']);
$config['avatar_path'] = bootstrap_build_path($bootstrap['images_dir'].'/avatars/');
$config['avatar_url'] = bootstrap_build_url($bootstrap['images_dir'].'/avatars/');
$config['captcha_path'] = bootstrap_build_path($bootstrap['images_dir'].'/captchas/');
$config['captcha_url'] = bootstrap_build_url($bootstrap['images_dir'].'/captchas/');
$config['captcha_path'] = bootstrap_build_path($bootstrap['images_dir'].'/captchas/');
$config['captcha_url'] = bootstrap_build_url($bootstrap['images_dir'].'/captchas/');
$config['emoticon_path'] = bootstrap_build_path($bootstrap['images_dir'].'/smileys/');
$config['emoticon_url'] = bootstrap_build_url($bootstrap['images_dir'].'/smileys/');
$config['photo_path'] = bootstrap_build_path($bootstrap['images_dir'].'/member_photos/');
$config['photo_url'] = bootstrap_build_url($bootstrap['images_dir'].'/member_photos/');
$config['prv_msg_upload_path'] = bootstrap_build_path($bootstrap['images_dir'].'/pm_attachments/');
$config['prv_msg_upload_url'] = bootstrap_build_url($bootstrap['images_dir'].'/pm_attachments/');
$config['sig_img_path'] = bootstrap_build_path($bootstrap['images_dir'].'/signature_attachments/');
$config['sig_img_url'] = bootstrap_build_url($bootstrap['images_dir'].'/signature_attachments/');
$config['theme_folder_path'] = bootstrap_build_path($bootstrap['themes_dir']);
$config['theme_folder_url'] = bootstrap_build_url($bootstrap['themes_dir']);
$config['third_party_path'] = bootstrap_build_path($bootstrap['third_party_dir']);
$config['tmpl_file_basepath'] = bootstrap_build_path($bootstrap['templates_dir']);
$config['snippet_file_basepath'] = bootstrap_build_path($bootstrap['templates_dir'].'/snippets/');
$config['save_tmpl_files'] = $bootstrap['save_templates_as_files'] ? 'y' : 'n';

// global environment variables
global $assign_to_config;
if ( ! isset($assign_to_config['global_vars']))
{
	$assign_to_config['global_vars'] = array();
}

$assign_to_config['global_vars']['global:env'] = getenv('EXP_ENV');

/* End of file bootstrap.php */

config.php

/* Add this to the bottom of system/expressionengine/config/config.php */

require(realpath(dirname(__FILE__).'/../../../bootstrap.php'));

database.php

/* Add this to the bottom of system/expressionengine/config/database.php */

require(realpath(dirname(__FILE__).'/../../../bootstrap.php'));

Have you had problems updating your version of EE b/c the $config's are in another file?