Feature/CI Workflow (#1)

# Add CI/CD Pipeline with Docker Build and Publish

## Summary
This PR adds a complete CI/CD pipeline for building and publishing Docker images of the Three.js game to the Forgejo container registry. The workflow automatically builds, validates, and publishes Docker images with semantic versioning when code is merged to main.

## Changes

### 🚀 CI/CD Workflow (`.forgejo/workflows/ci.yaml`)
- **Build & Validation**: Automatically builds Docker image on PRs and validates it works
- **Semantic Versioning**: Auto-increments patch version on each merge to main
  - First version: `0.1.0` (when no tags exist)
  - Subsequent merges: Auto-increments patch (e.g., `0.1.0` → `0.1.1` → `0.1.2`)
- **Publishing**: Publishes images to `git.jusemon.com/jusemon/threejs-test:<version>` and `latest` tag
- **Git Tagging**: Automatically creates git tags (e.g., `v0.1.0`) for releases
- **Registry Integration**: Uses Forgejo container registry with secrets-based authentication

### 🐳 Docker Setup
- **Dockerfile**: Custom nginx:alpine image with the game HTML file
- **docker-compose.yml**: Simple orchestration for local development
- **nginx.conf**: Minimal nginx configuration with gzip compression

## Workflow Behavior

### On Pull Requests
- ✅ Builds Docker image
- ✅ Validates image by running container and checking HTTP response
- ❌ Does NOT publish (validation only)

### On Merge to Main
- ✅ Builds Docker image
- ✅ Validates image
- ✅ Publishes to registry with version tag
- ✅ Tags as `latest`
- ✅ Creates git tag for the release

## Required Setup

Before merging, ensure these secrets are configured in the repository:
- `REGISTRY_USERNAME`: Forgejo username
- `REGISTRY_PASSWORD`: Personal Access Token with package write permissions

## Versioning Strategy

- **First Release**: `0.1.0` (when no tags exist)
- **Subsequent Releases**: Auto-increments patch version on each merge
- **Image Tags**:
  - `git.jusemon.com/jusemon/threejs-test:0.1.0`
  - `git.jusemon.com/jusemon/threejs-test:latest` (always points to latest main)

## Testing

The workflow includes validation steps that:
1. Build the Docker image
2. Run a test container
3. Verify the web server responds correctly
4. Only publish if all validations pass

## Benefits

- ✅ Automated builds and deployments
- ✅ Consistent versioning
- ✅ Image validation before publishing
- ✅ Easy rollback using version tags
- ✅ Latest tag for easy deployment

Reviewed-on: #1
Co-authored-by: Juan Sebastian Montoya <juansmm@outlook.com>
Co-committed-by: Juan Sebastian Montoya <juansmm@outlook.com>

.forgejo/workflows/ci.yaml

@@ -0,0 +1,100 @@
+name: Build and Publish Docker Image
+
+on:
+  pull_request:
+    branches:
+      - main
+  push:
+    branches:
+      - main
+
+jobs:
+  build-and-validate:
+    name: Build and Validate
+    runs-on: ubuntu
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build Docker Image
+        run: |
+          docker build -t threejs-test:test .
+
+      - name: Validate Image
+        run: |
+          docker run --rm -d --name test-container -p 8080:80 threejs-test:test
+          sleep 2
+          curl -f http://localhost:8080 || exit 1
+          docker stop test-container
+
+  publish:
+    name: Publish to Registry
+    runs-on: ubuntu
+    needs: build-and-validate
+    if: github.event_name == 'push' || gitea.event_name == 'push'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Fetch all history for tags
+
+      - name: Login to Registry
+        run: |
+          echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login git.jusemon.com -u "${{ secrets.REGISTRY_USERNAME }}" --password-stdin
+
+      - name: Determine Version
+        id: version
+        run: |
+          # Get latest version tag
+          LATEST_TAG=$(git describe --tags --match 'v*.*.*' --abbrev=0 2>/dev/null || echo "v0.0.0")
+          LATEST_VERSION="${LATEST_TAG#v}"
+          
+          # Parse version components
+          IFS='.' read -r MAJOR MINOR PATCH <<< "$LATEST_VERSION"
+          MAJOR=${MAJOR:-0}
+          MINOR=${MINOR:-0}
+          PATCH=${PATCH:-0}
+          
+          # Increment patch version for each merge to main, or start at 0.1.0 if no tags exist
+          if [[ "$LATEST_TAG" == "v0.0.0" ]]; then
+            # First version
+            NEW_VERSION="0.1.0"
+          else
+            # Increment patch version for each merge to main
+            PATCH=$((PATCH + 1))
+            NEW_VERSION="$MAJOR.$MINOR.$PATCH"
+          fi
+          
+          echo "version=$NEW_VERSION" >> $GITHUB_OUTPUT
+          echo "tag=v$NEW_VERSION" >> $GITHUB_OUTPUT
+          echo "Latest tag: $LATEST_TAG"
+          echo "New version: $NEW_VERSION"
+
+      - name: Build Docker Image
+        run: |
+          IMAGE_NAME="git.jusemon.com/jusemon/threejs-test:${{ steps.version.outputs.version }}"
+          docker build -t "$IMAGE_NAME" .
+          echo "IMAGE_NAME=$IMAGE_NAME" >> $GITHUB_ENV
+
+      - name: Push Docker Image
+        run: |
+          IMAGE_NAME="git.jusemon.com/jusemon/threejs-test:${{ steps.version.outputs.version }}"
+          docker push "$IMAGE_NAME"
+          
+          # Also tag as 'latest' for main branch
+          docker tag "$IMAGE_NAME" "git.jusemon.com/jusemon/threejs-test:latest"
+          docker push "git.jusemon.com/jusemon/threejs-test:latest"
+
+      - name: Create Git Tag
+        run: |
+          git config user.name "forgejo-actions"
+          git config user.email "forgejo-actions@forgejo.io"
+          TAG="${{ steps.version.outputs.tag }}"
+          # Check if tag already exists
+          if git rev-parse "$TAG" >/dev/null 2>&1; then
+            echo "Tag $TAG already exists, skipping tag creation"
+          else
+            git tag -a "$TAG" -m "Release ${{ steps.version.outputs.version }}"
+            git push origin "$TAG"
+          fi
+