How can i update the search index w/o using adminCP?

[Oreamnos]

i am going to make a script that will "post a new thread" when a user uses another function of my site, relatively unrelated to my forums.

i will be making an insert into db tables thread, post and updating user post count.

the only problem is updating the Search Index. how can i update the search index after i "manually" update the other db tables so that the post data will become searchable?

thanks
eric