how to add new cell to db and use it in admincp

[mosz]

Hello
I want to add one cell to table forum
it will be "forum_rules"
change in db is simple

But now i want to add into admincp site to add
rules (put in forum_rules) for each forums

how to do it ?

I was modifited admincp/forum.php (add new textarea like in description case) but it was make only errors after this modification

any idea how can i do it ?