DirectoryStorage keepclass feature
==================================

DirectoryStorage supports classes that need to keep their history
longer than normal.  This is useful if you want to keep all revisions
of a class for auditing purposes, or because you want to view extra
history of a class using a Zope *history* tab.

Class names are registered in the [keepclass] section of the config
file, together with a specification of how much extra time they should
be kept.  The following examples keep an extra week of history for
Zope DTML Methods never discard history for DTML Documents.  This
feature is of more use with application-specific class, and not
particularly useful for these standard document classes.

::

  [keepclass]
  OFS.DTMLMethod.DTMLMethod = extra 7
  OFS.DTMLMethod.DTMLDocument = forever
