postgresql - Postgres table column name restrictions? -

i did in psql:

create table if not exists apiss (skey text, time integer, user text, ip text); 

i get

error:  syntax error @ or near "user" line 1: ...ble if not exists apiss (skey text, time integer, user text,... 

i do:

create table if not exists apiss (skey text, time integer, userd text, ip text); 

it works.
note userd instead of user.

are there restrictions on column names table can have??
(postgressql v9.1.3)

here's nice table of reserved words in postgresql:
http://www.postgresql.org/docs/current/static/sql-keywords-appendix.html

it best avoid using words table- or column-names.
alternative, however, enclose identifier in double-quotes, e.g.:

create table if not exists apiss (     skey text,      time integer,      "user" text,      ip text);