pushkin db host should be redefined on cluster-level

Change-Id: I9820f43838d44623105c4adaf520bd0284a9d3a7
diff --git a/docker/swarm/stack/pushkin.yml b/docker/swarm/stack/pushkin.yml
index a1fc0a8..d0a3bce 100644
--- a/docker/swarm/stack/pushkin.yml
+++ b/docker/swarm/stack/pushkin.yml
@@ -8,6 +8,7 @@
     pushkin_ssl:
       enabled: false
     pushkin_db: pushkin
+    pushkin_db_host: ${_param:haproxy_postgresql_bind_host}
     pushkin_smtp_host: smtp.gmail.com
     pushkin_smtp_port: 587
     webhook_from: your_sender@mail.com
@@ -30,7 +31,7 @@
             POSTGRES_USER: ${_param:pushkin_db_user}
             POSTGRES_PASSWORD: ${_param:pushkin_db_user_password}
             POSTGRES_DB: ${_param:pushkin_db}
-            PUSHKINDBHOST: ${_param:postgresql_bind_host}
+            PUSHKINDBHOST: ${_param:pushkin_db_host}
             PUSHKINELASTICHOST: ${_param:pushkin_elasticsearch}
             WEBHOOK_FROM: ${_param:webhook_from}
             EMAIL_SENDER_PASSWORD: ${_param:pushkin_email_sender_password}