Add CI/CD pipeline and SDLC docs

.github/workflows/deploy.yml

@@ -0,0 +1,66 @@
+name: Deploy
+
+on:
+  push:
+    branches: [master]
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    
+    steps:
+      - uses: actions/checkout@v4
+      
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      
+      - name: Log in to Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=sha,prefix=
+            type=raw,value=latest
+      
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+  deploy:
+    runs-on: ubuntu-latest
+    needs: build-and-push
+    environment: production
+    
+    steps:
+      - name: Deploy to Hetzner
+        uses: appleboy/ssh-action@v1.0.3
+        with:
+          host: ${{ secrets.HETZNER_HOST }}
+          username: ${{ secrets.HETZNER_USER }}
+          key: ${{ secrets.HETZNER_SSH_KEY }}
+          script: |
+            cd /opt/shellmate
+            docker compose pull
+            docker compose up -d --remove-orphans
+            docker system prune -f