docs: add development database and testing documentation

README.md

@@ -161,6 +161,46 @@ DATABASE_URL="postgresql://username:password@localhost:5432/euchre_camp"
 DATABASE_SHADOW_URL="postgresql://username:password@localhost:5432/euchre_camp_shadow"
 ```
 
+## Development Database
+
+For development and testing, use a separate development database to avoid conflicts with production data.
+
+**Setup Development Database:**
+
+```bash
+# Create and setup the development database
+npm run db:setup-dev
+
+# Reset the development database (drops and recreates)
+npm run db:reset-dev
+
+# Clean development database (drop and recreate with migrations)
+npm run db:setup-dev:clean
+```
+
+**Environment Configuration:**
+
+The development database uses `.env.development` which is automatically configured for:
+- Database: `euchre_camp_dev`
+- NODE_ENV: `development`
+
+**Testing with Development Database:**
+
+```bash
+# Run unit tests (uses test database automatically)
+npm run test
+
+# Run acceptance tests (uses development database)
+npm run test:acceptance
+```
+
+**Test Data Cleanup:**
+
+All tests automatically clean up their created records:
+- Global setup/teardown handles Playwright tests
+- Test utilities provide `cleanupTestRecords()` for manual cleanup
+- Tests use `beforeEach` and `afterEach` hooks for automatic cleanup
+
 ## Usage
 
 ### Creating a Tournament