# PostgreSQL Environment Setup Progress - COMPLETED

## Overview
Setting up PostgreSQL support for JankenSQLHub with Docker for local development and GitHub Actions for CI/CD testing. Implementation follows experimental approach to keep core library unchanged.

## Completed Tasks
- [x] Task initialized - starting PostgreSQL environment setup
- [x] Add PostgreSQL dependencies (tokio-postgres) to Cargo.toml as dev-dependencies
- [x] Create Docker Compose configuration for local PostgreSQL development
- [x] Create experimental PostgreSQL test module instead of modifying core
- [x] Create GitHub Actions workflow for PostgreSQL testing in CI/CD
- [x] Implement PostgreSQL basic connectivity and database setup tests
- [x] Verify all tests pass (76 total tests, including 2 PostgreSQL experiments)
- [x] Update README.md with PostgreSQL setup instructions

## Implementation Notes
- **Experimental Approach**: PostgreSQL support is implemented through `tests/postgresql_experiments.rs` instead of modifying the core library to keep SQLite functionality stable
- **Isolated Testing**: Tests only run when `POSTGRES_CONNECTION_STRING` environment variable is set
- **CI/CD Integration**: GitHub Actions automatically provisions PostgreSQL and runs all tests
- **Local Development**: Docker Compose setup allows easy local PostgreSQL testing
- **Zero Breaking Changes**: All existing SQLite functionality remains unchanged

## Future PostgreSQL Integration
When ready to implement full PostgreSQL support in the core library:
1. Modify DatabaseConnection enum to include PostgreSQL variant
2. Implement QueryRunner trait for PostgreSQL
3. Create PostgreSQL-specific query execution functions in runner.rs
4. Add database switching configuration system
5. Update all existing tests to support dual database testing
