Add GitHub workflow

Author: Oscariremma

.github/workflows/docker.yml

@@ -0,0 +1,50 @@
+name: Docker
+
+on:
+  push:
+    branches: [main]
+    tags:
+      - v[0-9]+.[0-9]+.[0-9]+*
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    name: Build image
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository_owner }}/slack-strava-integration
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=sha
+            type=edge
+            type=ref,event=pr  
+
+      - name: Build Docker image (and push on main)
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max