Use Git dir to make redis config absolute path

docker/docker-compose.prod.yml

@@ -28,7 +28,7 @@ services:
       image: redis
       command: redis-server /etc/redis.conf
       volumes:
-          - ${PWD}/docker/redis.conf:/etc/redis.conf
+          - ${PORTAINER_GIT_DIR}/docker/redis.conf:/etc/redis.conf
       volumes_from:
           - tmp