add example port to firewall_allowed_tcp_ports

You can add to more the list of TCP ports to open to incoming traffic.

See more details:
https://github.com/vitabaks/postgresql_cluster/tree/master/roles/ansible-role-firewall

#52

vars/system.yml

@@ -122,17 +122,21 @@ firewall_allowed_tcp_ports_for:
     - "{{ postgresql_port }}"
     - "{{ pgbouncer_listen_port }}"
     - "8008"  # Patroni REST API port
+#    - "10050"  # Zabbix agent
+#    - ""
   etcd_cluster:
     - "{{ ansible_ssh_port | default(22) }}"
     - "2379"  # ETCD port
     - "2380"  # ETCD port
+#    - ""
   balancers:
     - "{{ ansible_ssh_port | default(22) }}"
     - "5000"  # HAProxy (read/write) master
     - "5001"  # HAProxy (read only) all replicas
     - "5002"  # HAProxy (read only) synchronous replica only
     - "5003"  # HAProxy (read only) asynchronous replicas only
     - "7000"  # HAProxy stats
+#    - ""
 
 firewall_additional_rules_for:
   master: []