ID sets up a basic framework for implementing an id
based sessioning service. Cookies sent to the client for maintaining
sessions will only contain an id reference. Only get_session and
set_session should need to be overwritten.
All parameters are optional.
- :key determines the name of the cookie, by default it is
‘rack.session‘
- :domain and :path set the related cookie values, by default domain is nil,
and the path is ’/’.
- :expire_after is the number of seconds in which the session cookie will
expire. By default it is set not to provide any expiry time.