One user, one mailbox, two different domains.

==== Required information ====
- iRedMail version: 0.8.6 FREE
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Linux/BSD distribution name and version: CentOS 6.5
- Related log if you're reporting an issue:
====

Hello everyone,

How to setup one user with only one mailbox receiving from two different domains (user1@domain1.com or user1@domain2.com)? Domain alias ?

Scenario:
Someone sends an email to user1@domain1.com or user1@domain2.com  and user1 checks his only one mailbox and gets the email.

Thanks for the support.