postgres=# CREATE USER wmanager;
CREATE ROLE
postgres=# alter user wmanager WITH PASSWORD  'xxxx';
ALTER ROLE
postgres=# 

[root@mon publics]# su - postgres
-bash-4.1$ psql 
psql (8.4.20)
Type "help" for help.
postgres=# create database demo_wmanager_org;
CREATE DATABASE
postgres=# 

postgres=# alter DATABASE demo_wmanager_org owner to wmanager;
ALTER DATABASE

-bash-4.1$ psql demo_wmanager_org -U wmanager -W
Password for user wmanager: 
psql (8.4.20)
Type "help" for help.

demo_wmanager_org=> 

WManger uses your default postgres settings. If you want to explicit setting to your database:

ALTER DATABASE demo_wmanager_org SET datestyle TO "SQL, DMY";