Use server on a primary domain name, instead of virtual host.

==== Required information ====
- iRedMail version: 0.9.0
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Linux/BSD distribution name and version: Debian 7
- Related log if you're reporting an issue:
- Nginx
====

Hello,

i am trying to have iRedMail to use primary domain instead of virtual host, but i can't figure out how.

Here is the example:

For example I have domain myserver.com. iRedMail installer asks me to define a virtual host to be used as email domain.
I am entering 'mail' and have following as result: mail.myserver.com.
And all emails have addresses like postmaster@mail.myserver.com.

So my question is - how to make iredmail work on the primary domain and have email like postmaster@myserver.com
instead of postmaster@mail.myserver.com?

Also i'd like to know, how to make mail.myserver.com address for roundcube accessing.

Thanks!