command line tool to manage vsftpd users stored in a mysql db
I wrote an article on how to get a vsftpd server working with chrooted users stored in a mysql table. Currently it is written in Italian, but the steps you need are pretty clear, I will translate it in english as soon as I get a bit of free time.
http://www.petrelli.biz/2017/05/17/vsftpd-con-utenti-mysql-e-custom-chrooted-homedir/