Hide ip address

Dear All,

this is my second post. I try to set up nginx on a centos machine. I managed to make it respond to the domain name but I could not configure two different server blocks... Also, when I type my domain name (example.com) I go to th eindex page of the server but in the url is my ip address instead of the domain name. How can I fix that? I installed the lates version of nginx via the passenger gem for Rails.

Any help will do ! :)

Thanks!