Restore note about custom db class in README

[marvinthepa]

I am not sure if this is correct, but it seems to me that the rake task does not work if users are using a custom class (especially if the table name is different).

My suggestion is to restore the old note.

[ghiculescu]

alternatively, #179

[marvinthepa]

alternatively, #179

@ghiculescu I think this is something different. This part of the README references the db:sessions:upgrade task, #179 is about trim.

[ghiculescu]

Ooops I misread your changes, sorry!

[ghiculescu]

It does seem to me like the sessions upgrade task respects custom classes though? https://github.com/rails/activerecord-session_store/blob/master/lib/tasks/database.rake#L24

[marvinthepa]

It does seem to me like the sessions upgrade task respects custom classes though?

It tries to use the custom class. But it will not work if the custom class does not have a secure! method. Maybe instead of this, it should be mentioned in the README that the custom class needs to copy the secure! method from ActiveRecord::SessionStore::Session.
I do not know, I just wanted to start a discussion on how to correctly point the users in the right direction.

[ghiculescu]

Maybe instead of this, it should be mentioned in the README that the custom class needs to copy the secure! method from ActiveRecord::SessionStore::Session.

I like this idea. Have implemented in #179 as part of the other stuff I'm doing, and added you as a co-author.