Openshift and Rails 3.2

I should upload a simple app in Openshift The app is a test , it's nothing complex. It should just have a single controller used to add smething in a Mysql DB. I followed many tutorials on internet , in how to set Openshift and Rails , and i was able to see the Welcome page of a Rails project. However , i wasn't able to set properly my MySQL database. I have to use the openshift database , and i have to put their Variable enviroments , such as:

OPENSHIFT_MYSQL_DB_HOST
OPENSHIFT_MYSQL_DB_USERNAME

etc..

to be able to connect to my database. The problem is , i'm able to create a project from my shell to my openshift account (so i think git and rhc are linked) but i'm not able to see the env variables. I mean , if i write:

 rhc env list -a <appname>

i'll not see nothing.

So, i think something is wrong here. Can you help me , and say something more about the config (development, production..) of a Rails app?