Save extra data

[Mohammadreza Shahsahebi]

Hi, I want to store data related to each user, and their choice in a new database with a couple of extra calculation. I read about ExtraModel but it seems like it doesn't have the option to store the data unless you use custom export (which I don't know how to implement). How can I create a new database in otree for that, or better put, what is the best solution for my problem?

Thanks