pdns-admin only to master,

add mariadb replica

docker-compose.master.yml

@@ -9,6 +9,8 @@ services:
       MARIADB_DATABASE: ${MARIADB_DATABASE}
       MARIADB_USER: ${MARIADB_USER}
       MARIADB_PASSWORD: ${MARIADB_PASSWORD}
+      MARIADB_REPLICATION_USER: ${MARIADB_REPLICA_USER}
+      MARIADB_REPLICATION_PASSWORD: ${MARIADB_REPLICA_PASSWORD}
     volumes:
       - mariadb_data:/var/lib/mysql
     networks: