remove zulip admin env and add secrets decleration to services

compose.yml

@@ -19,8 +19,10 @@ services:
       SETTING_RABBITMQ_HOST: "rabbitmq"
       SETTING_REDIS_HOST: "redis"
       SETTING_EXTERNAL_HOST: ${DOMAIN}
-      SETTING_ZULIP_ADMINISTRATOR: "admin@example.com"
       ZULIP_AUTH_BACKENDS: "EmailAuthBackend"
+    secrets:
+      - zulip_secret
+      - smtp_password
     volumes:
       - "zulip:/data:rw"
     ulimits:
@@ -102,6 +104,8 @@ services:
         target: /custom-entrypoint.sh
         mode: 555
     entrypoint: /custom-entrypoint.sh
+    secrets:
+      - redis_password
     command:
       - "sh"
       - "-euc"