proposal for a CookBook in postgresql.org

I just saw a beatifull answer from Pavel, as an answer to this question:
"""
I'm just wondering if there's some way to retrieve the hour column as the
> sum of the array values... Just like this:
>
>            hour            | statistics_date
> ----------------------------+-----------------
>  9000                       | 2008-01-03
"""

With this function:
"""
postgres=# create or replace function sum_items(bigint[]) returns
bigint as $$ select sum($1[i])::bigint from
generate_series(array_lower($1,1), array_upper($1,1)) g(i)$$ language
sql immutable;
CREATE FUNCTION
Time: 2,510 ms
postgres=# select sum_items(array[1,2,3,4]); sum_items
-----------       10
(1 row)
"""

I think this is a good time to propose some kind of CookBook, to
preserve this kind of answers.

Gerardo