如何在OpenShift上配置CodeIgniter连接？

I just finished my php application so I decided to try it on my online account OpenShift. I created a new application and I imported PHP 5.3, MySQL and phpMyAdmin. I then uploaded via filezilla my application in the app-root/data/Calendar, I think it's the right folder where to upload the projects. Within the Calendar folder is my php application.
I then inserted these credentials in the configuration.php file:

<?php
class SystemConfiguration 
{
    // General Settings
    public static $base_url    = 'first-johncloun.rhcloud.com/Calendar/';

    // Database Settings
    public static $db_host     = 'mysql://$OPENSHIFT_MYSQL_DB_HOST:$OPENSHIFT_MYSQL_DB_PORT/';
    public static $db_name     = 'first';
    public static $db_username = 'admisawhiN';
    public static $db_password = '*****';

}

Are the credentials for my database. So I put this url first-johncloun.rhcloud.com/Calendar/ to connect to my application but is displayed:

404 Page not found

What did I do wrong? Someone could help me? I'm new on OpenShift.

First of all I'd like to point out that you should really be using git to deploy your application, see: https://developers.openshift.com/en/managing-modifying-applications.html

However, if you really want to stick to ftp upload, according to the openshift documentation you should upload your app to:

/app-root/repo/php