Envrionment Variable ADD_DEFAULT_DATA is not documented

[maxswjeon]

Summary

Environment Variable ADD_DEFAULT_DATA is not documented

Steps to reproduce

Search ADD_DEFAULT_DATA in README.md -> Not found

What is the expected correct behavior?

Add documentation for ADD_DEFAULT_DATA

Relevant logs and/or screenshots

Environment

• Image version / tag:
• Host OS:

Any logs | docker-compose.yml

We should document that if custom script exists, ADD_DEFAULT_DATA is ignored as well as ENABLE_READONLY_USER

Possible fixes

1. Add documentation
2. Execute ADD_DEFAULT_DATA and ENABLE_READONLY_USER sequence even if we have custom scripts