Improve docker setup

- add .dockerignore to reduce build context
- add entrypoint.sh to initialize environment before user switch
- fix Celery setting deprecation warnings
- downgrade importlib-metadata for Celery compatibility
- set TZ environment variable for consistent Celery timestamps

pyproject.toml

@@ -11,6 +11,7 @@ python = "^3.7"
 celery = "^5.2.7"
 mysqlclient = "^2.1.1"
 redis = "^4.5.1"
+importlib-metadata = "<5"
 
 
 [tool.poetry.group.dev.dependencies]