Create some kind of log

[simark]

A log of all the operations that happen would be nice:

• User created
• User login
• Debt added
• Debt confirmed
• ???

I guess we could use a singleton class like we do for the session right now. It would allow any part of the application to use it, and we could do some filtering at the class entry point used to log something. Ideally, it would be possible to configure the destination of the log. For example, a text TextLogger class could send the log to a text file, DBLogger could write it in a DB, NetworkLogger could send it over the network using an arbitrary format (I'm thinking about this one here http://www.efficios.com/ctf, but there might be other good formats out there).

[eepp]

Yes and we also need some history in the DB:

• user login/logout (date, IP address)
• debts: since we cannot delete debts now, this is already implemented by the debts table, but we also need validate/invalidate dates
• eventually: groups history