cd /etc/postgresql/9.x/main/
open file named postgresql.conf
sudo vi postgresql.conf
add this line to that file
listen_addresses="*"
then open file named pg_hba.conf
sudo vi pg_hba.conf
and add this line to that file
host all all 0.0.0.0/0 md5
It allows access to all databases for all users with an encrypted password
restart your server
sudo /etc/init.d/postgresql restart