fix celery permission warnings in container

[BoYanZh]

joj/tiger/tests/test_main.py::test_add
  /root/.venv/lib/python3.8/site-packages/celery/platforms.py:840: SecurityWarning: You're running the worker with superuser privileges: this is
  absolutely not recommended!
  
  Please specify a different user using the --uid option.
  
  User information: uid=0 euid=0 gid=0 egid=0
  
    warnings.warn(SecurityWarning(ROOT_DISCOURAGED.format(

-- Docs: https://docs.pytest.org/en/stable/warnings.html