disable an user

[andreaubbiali]

@sgotti We want to disable the user when he doesn't work anymore in the company.
We have thought different ways:

-Creating a new column in the database with a check if he still works or not. Then in the query, when we request the member, we have to control if this column is checked or not.

-If there is already in the database a column with something that allows to know if he is working or not we can use it. For example if there is the contract expiration date we can compare it with the current date and disable users with the date lower than it.