Use mysql users with Postfix

[AndDM]

Hi, I'm new of mail server and roundcube. I've install Postfix+Dovecot+Mysql as mail server and It works, but now I want install roundcube and set It to use the mysql users.
I've a database mail with a table users and, in this table, the fields email and password.
Now, I must install the other table of roundcube schema, add the fields in the table user and set the connect of roundcube to this database. Is It right?

Thanks, bye.

[JohnDoh]

The RoundCube database should be separate; RC is an IMAP client it authenticates against your IMAP server and not any backend directly.

[AndDM]

Hi JohnDoh, so can't I use postfix user? Now I've link the postfix configuration to RC table users, I hope that I use this to manage the virtual user.
So I can enter with root or dovecot user credential, where I set the password?

EDIT: I'm sorry, It works. For my configuration i must set auto_create_user true. Thanks for your time.