Add an additional column to the user-table to allow user identification

Add an additional column to the user-table to allow user identification: Is your feature request related to a problem? Please describe. I import users from csv-file, using a script. The Username is generated out of firstname and lastname. Using the - in the csv-file also excisting -unique-id is not user-friendly because the username is the login-name. If firstname or lastname changes, there will be generated a new user instead of updating the old one. The only way to identify the excisting user would be by unique-id which can't be added anywhere. As described here it would be very hard to...