Refer to the finally uploaded content in the following task (http://www.google-melange.com/gci/task/view/google/gci2012/8098207)

Here each file contains hostname, username and password therefore it is not easy to install the app.

eg:

$link = mysql_connect('localhost', 'root', 'root');

Your task is to create a file for ex: config.php and all credentials (hostname, username and password) will be added to that file as variables. Then include the config.php file to each file sing include(); function.

Then it is easy to change credentials in one file (config.php) then it will effect for whole system.