User tracking mod

[GDOrn]

User tracking mod is incredibly slow as written. There's a few reason for it.

First, dates are being stored as a varchar. That's bad, but workable.
Second, there's no useful index in the table. To fix this, either use phpmyadmin to add an index on session_id, or use install sql patches in the zc admin to run the following:

ALTER TABLE `user_tracking` ADD INDEX ( `time_entry` );
ALTER TABLE `user_tracking` ADD INDEX ( `session_id` );
ALTER TABLE `user_tracking` ADD INDEX ( `time_entry` );

You will need to change `user_tracking` to include any table prefix, if you're using one.

This will speed up the User tracking admin page by a ton, with a slight increase in mysql table size.