feat: add SQLite database isolation by branch and documentation

Extend branch isolation to SQLite databases for local development
and add comprehensive documentation for the branch isolation feature.

Changes to SQLite isolation:
- Modify dev.py to use branch-specific SQLite files (db-{branch}.sqlite3)
- Add *.sqlite3 to .gitignore to exclude database files
- Remove debug print statement from dev.py
- Each branch now has isolated SQLite data without requiring worktrees

Documentation improvements:
- Add complete "Docker Branch Isolation" section to README.md
- Document all branch:* commands (info, verify, volumes, clean)
- Add examples for multi-branch development and branch switching
- Add troubleshooting section for database configuration issues
- Update DOCKER-BRANCHES.md to mention SQLite isolation
- Add note in local setup about GIT_BRANCH export

New Taskfile command:
- task branch:verify - Comprehensive verification of branch configuration
  Shows git branch, expected database, .env file, and PostgreSQL databases

This ensures complete data isolation between branches whether using
Docker (PostgreSQL) or local development (SQLite), preventing data
loss when switching branches.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: matrixise

.gitignore

@@ -73,6 +73,7 @@ production.env
 # Database dumps and local databases
 *.dump
 *.duckdb
+*.sqlite3
 
 # Local settings
 pythonie/pythonie/settings/pgdev.py

DOCKER-BRANCHES.md

@@ -20,6 +20,7 @@ The system automatically:
 Each branch gets:
 - ✅ Its own Docker image
 - ✅ Its own PostgreSQL database (isolated data)
+- ✅ Its own SQLite database for local dev: `pythonie/db-{branch}.sqlite3`
 - ✅ Its own Redis instance (isolated cache)
 - ✅ Its own Docker volumes (persistent storage)
 - ✅ Unique container names (no conflicts)

README.md

@@ -12,6 +12,8 @@ Website for Python Ireland (python.ie / pycon.ie) community, built with Django 6
 
 ## Quick Start (Docker - Recommended)
 
+**Note**: Each git branch automatically gets its own isolated database and Docker environment. See [Docker Branch Isolation](#docker-branch-isolation) below.
+
 1. Build the Docker image:
    ```bash
    task docker:build
@@ -20,7 +22,7 @@ Website for Python Ireland (python.ie / pycon.ie) community, built with Django 6
 
 2. Start supporting services:
    ```bash
-   docker compose up -d postgres redis minio
+   docker compose up -d postgres redis
    ```
 
 3. Run database migrations:
@@ -48,10 +50,79 @@ Website for Python Ireland (python.ie / pycon.ie) community, built with Django 6
 7. Visit http://127.0.0.1:8000/ to see the site with sample content
 8. Access Wagtail admin at http://127.0.0.1:8000/admin/
 
+## Docker Branch Isolation
+
+The project automatically isolates Docker environments by git branch, allowing you to work on multiple branches simultaneously without conflicts.
+
+### How It Works
+
+Each git branch gets:
+- **Separate Docker image**: `python.ie/website:{branch-name}`
+- **Isolated PostgreSQL database**: `pythonie_{branch-name}` (for docker-compose with pgdev settings)
+- **Isolated SQLite database**: `pythonie/db-{branch-name}.sqlite3` (for local dev)
+- **Dedicated volumes**: `pythonie-postgres-data-{branch}`, `pythonie-redis-data-{branch}`
+- **Unique containers**: `pythonie-web-{branch}`, `pythonie-postgres-{branch}`, `pythonie-redis-{branch}`
+
+### Branch Commands
+
+```bash
+# Check your current branch environment
+task branch:info
+
+# Verify database configuration
+task branch:verify
+
+# List all Docker volumes (all branches)
+task branch:volumes
+
+# Clean up volumes for current branch (DESTRUCTIVE!)
+task branch:clean
+```
+
+### Working on Multiple Branches
+
+**Scenario**: Work on `main` and `feature/new-auth` simultaneously.
+
+```bash
+# Terminal 1: Main branch on default ports
+git checkout main
+task run  # Uses pythonie_main database on port 8000
+
+# Terminal 2: Feature branch on custom ports
+git checkout feature/new-auth
+WEB_PORT=8001 PG_PORT=5433 task run  # Uses pythonie_feature-new-auth on port 8001
+```
+
+### Switching Branches
+
+When you switch branches, the system automatically uses the correct environment:
+
+```bash
+git checkout main
+task run  # Automatically uses main database
+
+git checkout feature/xyz
+task run  # Automatically uses feature-xyz database (isolated from main)
+```
+
+**Note**: Rebuild the Docker image after switching branches if dependencies changed:
+```bash
+git checkout feature/new-dependencies
+task docker:build
+task run
+```
+
+For detailed documentation, see [DOCKER-BRANCHES.md](DOCKER-BRANCHES.md).
+
 ## Local Setup (Without Docker)
 
 If you prefer to develop without Docker:
 
+**Note**: When developing locally, each git branch automatically uses its own SQLite database (`db-{branch}.sqlite3`). Export `GIT_BRANCH` for automatic isolation:
+```bash
+export GIT_BRANCH=$(git rev-parse --abbrev-ref HEAD | sed 's/[^a-zA-Z0-9._-]/-/g' | tr '[:upper:]' '[:lower:]')
+```
+
 1. Fork the repository into your own personal GitHub account
 2. Clone your fork: `git clone git@github.com:YourGitHubName/website.git`
 3. Ensure you are running Python 3.13: `python -V` should output `Python 3.13.x`
@@ -134,6 +205,12 @@ task heroku:releases          # Show deployment history
 task heroku:rollback          # Rollback to previous release
 task heroku:maintenance:on    # Enable maintenance mode
 task heroku:maintenance:off   # Disable maintenance mode
+
+# Branch Isolation (Docker)
+task branch:info              # Show current branch and environment info
+task branch:verify            # Verify database configuration
+task branch:volumes           # List all Docker volumes (all branches)
+task branch:clean             # Remove volumes for current branch (CAUTION!)
 ```
 
 ### Direct Django Commands
@@ -257,6 +334,12 @@ This project uses several tools to streamline development:
 - Rebuild Docker image: `task docker:build`
 - Reinstall dependencies: `pip install -r requirements.txt`
 
+### Wrong Database Being Used
+- Check current branch: `git branch`
+- Verify environment: `task branch:info`
+- Check database configuration: `task branch:verify`
+- Ensure .env file is up to date: `task env:write`
+
 ## Contributing
 
 1. Fork the repository into your own GitHub account

Taskfile.yaml

@@ -302,3 +302,16 @@ tasks:
       - docker volume rm pythonie-postgres-data-{{.GIT_BRANCH}} 2>/dev/null || echo "Postgres volume not found"
       - docker volume rm pythonie-redis-data-{{.GIT_BRANCH}} 2>/dev/null || echo "Redis volume not found"
       - echo "Volumes cleaned for branch {{.GIT_BRANCH}}"
+
+  branch:verify:
+    desc: Verify database configuration for current branch
+    cmds:
+      - echo "=== Branch Configuration ==="
+      - echo "Git branch → {{.GIT_BRANCH}}"
+      - echo "Expected database → pythonie_{{.GIT_BRANCH}}"
+      - echo ""
+      - echo "=== Docker Environment ==="
+      - cat .env 2>/dev/null || echo ".env file not found (run any docker compose task to generate)"
+      - echo ""
+      - echo "=== PostgreSQL Databases ==="
+      - docker exec pythonie-postgres-{{.GIT_BRANCH}} psql -U postgres -c "\l" 2>/dev/null | grep pythonie || echo "PostgreSQL container not running"

pythonie/pythonie/settings/dev.py

@@ -16,10 +16,12 @@
 WAGTAILADMIN_BASE_URL = "http://localhost:8000"
 
 # SQLite (simplest install)
+# Database name includes git branch for isolation between branches
+GIT_BRANCH = os.environ.get("GIT_BRANCH", "dev")
 DATABASES = {
     "default": {
         "ENGINE": "django.db.backends.sqlite3",
-        "NAME": join(PROJECT_ROOT, "db.sqlite3"),
+        "NAME": join(PROJECT_ROOT, f"db-{GIT_BRANCH}.sqlite3"),
     }
 }