1/
Allow user to pass a group mapping in manage_groups=True mode.
A group mapping is a structure like:
{
"ldap_grp1": ["web2py_grp1", "web2py_grp2"],
"ldap_grp2": ["ldap_grp2", "web2py_grp3"],
}
After fetching the ldap user's ldap groups, the list entries are
translated, before janitoring the auth_group and auth_membership
tables.
2/
Allow to define a callback to execute if the auth_group or
auth_membership tables are changed.
Typical use-case are cache flushing and app-driven replication.
