create user and language.
1. sudo apt-get install postgresql
2. sudo -u postgres psql template1 -c "create user fei with superuser";
3. psql template1
4. template1=# create language plpgsql;

create user and password
2. sudo -u postgres createuser mystaff
3. sudo -u postgres psql template1
4. template1=#alter user mystaff password 'password'