Added missing postgreSQL install file

Converted to pgsql format from the mysql install file.
Also added missing comment syntax for config.php.

Proposed fix for issue with invalid redirection after making a new form.
Issue discovered when trying to make a new form and getting redirected to the edit page using an empty id GET.
See comments in commit for more detail on the fix.
`put()` should always populate the ID field from calling `DB::last_id()`. I wonder if it's because the id fields are defined as `serial` versus creating a sequence and using `default nextval('#prefix#table_seq')` like those in the main `conf/install_pgsql.sql`. I don't have Postgres installed on my machine here, so can you check if using sequences instead fixes it?