[phpOpenTracker-general] Documentation of 'pot_add_data'?

Hi there

I'm pondering how best to do a bit of extending of the phpOpenTracker
Logging Engine in order to add some extra fields associated with our
documents (codes identifying the section and topic within the website,
for example) for a CMS we're using.

Initially I thought I might use the pot_add_data additional data table
for simplicity, but it appears that the additional data table is linked
back to the unique *access* rather than to the *document*. This might be
something that could be added to the documentation - the pot_add_data
table is also missing from the phpOpenTracker schema, at least in the
english version of the docs.

I'll plough on what I have already for this, but if anyone has any code
that performs similar sutff for adding extra fields to the *documents*
in the database, then I'd be keen hear.

Cheers
JP