BDMS-463: Docker Compose Update

[chasetmartin]

Why

This PR addresses the following problem / context:

• The app container did not set POSTGRES_PORT, so it could read the host .env value (54321) or a non-container default. If it uses 54321 inside Docker, db connection will fail because the database is only listening on 5432 within the Docker network.
• README.md did not completely reflect potential docker development workflow

How

Implementation summary - the following was changed / added / removed:

• Added POSTGRES_PORT=5432 to the app service environment in docker-compose.yml to ensure container-to-container connections use the internal DB port
• Update README.md

Notes

Any special considerations, workarounds, or follow-up work to note?

• The db service still maps 54321:5432; local tools and commands should use POSTGRES_PORT=54321 to communicate to the db service, like setup with the .env.example

[Copilot]

Pull request overview

This PR fixes a Docker networking issue where the app container was missing an explicit POSTGRES_PORT environment variable, causing it to potentially use the wrong port when connecting to the database container.

Changes:

• Set POSTGRES_PORT=5432 in the app service environment to ensure correct container-to-container database connections
• Restructured README.md to clarify the two development workflow options (local PostgreSQL vs Docker Compose)
• Added documentation about port mapping (5432 internal, 54321 external) and when to use each

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
docker-compose.yml	Added POSTGRES_PORT=5432 environment variable to the app service to fix database connection
README.md	Reorganized and clarified development setup options, replacing table layout with clearer sections and adding notes about port configuration