📝 docs: update CI/CD documentation for container/services approach

README.md

@@ -43,11 +43,69 @@ go run ./cmd/greet
 
 ## CI/CD Pipeline
 
-dance-lessons-coach includes a portable CI/CD pipeline using GitHub Actions syntax:
+dance-lessons-coach features an optimized CI/CD pipeline using GitHub Actions with container/services architecture:
 
-### Features
-- ✅ **Multi-platform**: Works on Gitea, GitHub, and GitLab
-- ✅ **Build & Test**: Automated Go builds and tests
+### Key Features
+- ✅ **Container-based execution**: All steps run in pre-built Docker cache images
+- ✅ **Service-based PostgreSQL**: Automatic database service provisioning
+- ✅ **Smart caching**: Dependency-aware cache invalidation
+- ✅ **Multi-platform**: Compatible with Gitea, GitHub, and GitLab
+- ✅ **Fast execution**: No Docker Compose overhead
+- ✅ **Reliable testing**: Full database connectivity with proper environment setup
+
+### Architecture
+
+The pipeline uses GitHub Actions' native `container` and `services` directives instead of Docker Compose:
+
+```yaml
+jobs:
+  ci-pipeline:
+    container:
+      image: gitea.arcodange.lab/arcodange/dance-lessons-coach-build-cache:${{ needs.build-cache.outputs.deps_hash }}
+    
+    services:
+      postgres:
+        image: postgres:15
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: dance_lessons_coach_bdd_test
+```
+
+### Benefits
+
+1. **Performance**: Direct container execution without compose overhead
+2. **Reliability**: Service containers managed by GitHub Actions
+3. **Simplicity**: Cleaner workflow definition
+4. **Portability**: Works across CI platforms
+5. **Caching**: Intelligent dependency-based cache rebuilding
+
+### Workflow Steps
+
+1. **Build Cache**: Creates Docker image with Go tools and dependencies
+2. **CI Pipeline**: Runs tests, builds binaries, and generates documentation
+3. **Database Tests**: Connects to PostgreSQL service container
+4. **Coverage Reporting**: Updates coverage badges automatically
+5. **Artifact Publishing**: Builds and pushes Docker images (main branch only)
+
+### Environment Configuration
+
+The pipeline automatically sets up database environment variables:
+
+```bash
+echo "DLC_DATABASE_HOST=postgres" >> $GITHUB_ENV
+echo "DLC_DATABASE_PORT=5432" >> $GITHUB_ENV
+echo "DLC_DATABASE_USER=postgres" >> $GITHUB_ENV
+echo "DLC_DATABASE_PASSWORD=postgres" >> $GITHUB_ENV
+echo "DLC_DATABASE_NAME=dance_lessons_coach_bdd_test" >> $GITHUB_ENV
+echo "DLC_DATABASE_SSL_MODE=disable" >> $GITHUB_ENV
+```
+
+### Status
+
+[![Build Status](https://gitea.arcodange.fr/api/badges/arcodange/dance-lessons-coach/status)](https://gitea.arcodange.fr/arcodange/dance-lessons-coach)
+[![Coverage](https://img.shields.io/badge/coverage-0%-red?style=flat-square)](https://gitea.arcodange.lab/arcodange/dance-lessons-coach)
+=======
 - ✅ **Linting**: Code quality checks with `go fmt` and `go vet`
 - ✅ **Version Management**: Automatic version detection
 - ✅ **Portable**: Uses standard GitHub Actions workflow format