Add GitHub Actions workflow for Docker container build and push

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

.github/workflows/docker-build.yml

@@ -0,0 +1,74 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+      - master
+    tags:
+      - 'v*'
+  pull_request:
+    branches:
+      - main
+      - master
+  workflow_dispatch:
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Container Registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=sha,prefix={{branch}}-
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push Docker image
+        id: build
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          platforms: linux/amd64,linux/arm64
+
+      - name: Generate artifact attestation
+        if: github.event_name != 'pull_request'
+        uses: actions/attest-build-provenance@v1
+        with:
+          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}
+          subject-digest: ${{ steps.build.outputs.digest }}
+          push-to-registry: true

README.md

@@ -22,7 +22,39 @@ A Docker-based solution that automatically fetches emails from POP3 mailboxes an
 - POP3 account credentials
 - (Optional) Postmarkapp account for error notifications
 
-### Setup
+### Option 1: Using Pre-built Docker Image (Recommended)
+
+The Docker images are automatically built and published to GitHub Container Registry.
+
+1. **Create configuration file**
+   ```bash
+   # Download the docker-compose.yml and .env.example
+   curl -O https://raw.githubusercontent.com/christianlouis/pop_puller_to_gmail/main/docker-compose.yml
+   curl -o .env https://raw.githubusercontent.com/christianlouis/pop_puller_to_gmail/main/.env.example
+   
+   # Edit .env with your credentials
+   nano .env
+   ```
+
+2. **Update docker-compose.yml to use the pre-built image**
+   ```yaml
+   version: '3.8'
+   
+   services:
+     pop3-forwarder:
+       image: ghcr.io/christianlouis/pop_puller_to_gmail:latest
+       container_name: pop3-gmail-forwarder
+       restart: unless-stopped
+       env_file:
+         - .env
+   ```
+
+3. **Run the container**
+   ```bash
+   docker-compose up -d
+   ```
+
+### Option 2: Building from Source
 
 1. **Clone the repository**
    ```bash
@@ -69,6 +101,30 @@ A Docker-based solution that automatically fetches emails from POP3 mailboxes an
    docker-compose logs -f
    ```
 
+## Using Pre-built Docker Images
+
+Docker images are automatically built and published to GitHub Container Registry for every release and commit to the main branch.
+
+### Available Image Tags
+
+- `ghcr.io/christianlouis/pop_puller_to_gmail:latest` - Latest build from main branch
+- `ghcr.io/christianlouis/pop_puller_to_gmail:v1.0.0` - Specific version tags
+- `ghcr.io/christianlouis/pop_puller_to_gmail:main` - Main branch builds
+
+### Pull and Run
+
+```bash
+# Pull the latest image
+docker pull ghcr.io/christianlouis/pop_puller_to_gmail:latest
+
+# Run directly with Docker
+docker run -d \
+  --name pop3-forwarder \
+  --env-file .env \
+  --restart unless-stopped \
+  ghcr.io/christianlouis/pop_puller_to_gmail:latest
+```
+
 ## Configuration
 
 ### POP3 Accounts

docker-compose.yml

@@ -2,7 +2,11 @@ version: '3.8'
 
 services:
   pop3-forwarder:
+    # Option 1: Build from source (default)
     build: .
+    # Option 2: Use pre-built image from GitHub Container Registry
+    # Uncomment the line below and comment out 'build: .' to use pre-built image
+    # image: ghcr.io/christianlouis/pop_puller_to_gmail:latest
     container_name: pop3-gmail-forwarder
     restart: unless-stopped
     env_file: