Extend CI_Session_database_driver to work with extra cols in ci_sessions table

That file should be put into application/libraries/Session/drivers/, not application/core/ ...

However, there's very sensitive code in the drivers' files and you'd need to update your extension for every bugfix that they get. I'd consider another solution if I were you.

Well this is an application that will be bundled up and installed by whoever uses it as a whole, not managed as a website using a CI framework, but rather as an application, all updates will be coming from me, so I would be able to control that.

I think ill create an association table, then just create a wrapper around the write and destroy methods, but not change the methods themselves.

So it just creates the record in the association table or deletes it, then executes the correct method in the CI_Session_database_driver class