I am currently running a login site and want to add roundcube. It works fine. How do I take existing usernames/passwords from an existing db and add them to the roundcube db so that users in my current database can just click on a link to their new web mail account?
Also, how do I automatically create the roundcube account when they sign up for the main website?
Check RoundCube database, table 'users' and create those entries. Password is an MD5 hash.
But I think that's not the point. You have to create users on your IMAP server. RoundCube users a created automatically - if allowed in main.inc.php - on successfull imap login.