Added health check for database

roles/docker-mailu/templates/docker-compose.yml.j2

@@ -19,7 +19,11 @@ services:
       MYSQL_RANDOM_ROOT_PASSWORD: 'yes'
     volumes:
       - database:/var/lib/mysql
-
+    healthcheck:
+      test: "/usr/bin/mysql --user=mailu --password={{mailu_database_password}} --execute \"SHOW DATABASES;\""
+      interval: 3s
+      timeout: 1s
+      retries: 5
   # Core services
   front:
     image: ${DOCKER_ORG:-mailu}/${DOCKER_PREFIX:-}nginx:${MAILU_VERSION:-1.8}
@@ -39,6 +43,9 @@ services:
     volumes:
       - "/etc/mailu/overrides/nginx:/overrides"
       - "/etc/mailu/certs:/certs"
+    depends_on:
+      database:
+        condition: service_healthy
   admin:
     image: ${DOCKER_ORG:-mailu}/${DOCKER_PREFIX:-}admin:${MAILU_VERSION:-1.8}
     restart: always