move read messages

[dagod]

Hello,

my webhoster (all-inkl.de) allows only 500mb emails to be in the inbox (called 'Postfach'). Therefore i have to move emails after reading into another folder i call 'Gelesen' ('read').
How can i do this automaticly, so that roundcube moves my emails in the folder 'Gelesen' after i have read them?

Thanks for your help.