ci: add build workflow

Author: vojtechmares

.github/workflows/build.yml

@@ -0,0 +1,54 @@
+name: Docker build
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-24.04
+
+    permissions:
+      contents: read
+      packages: write # required to push to ghcr.io
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up qemu
+      uses: docker/setup-qemu-action@v3
+
+    - name: Set up docker
+      uses: docker/setup-buildx-action@v3
+
+    - name: Login to GitHub Container Registry
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Docker metadata
+      uses: docker/metadata-action@v5
+      id: meta
+      with:
+        images: |
+          ghcr.io/${{ github.repository }}
+        tags: |
+          type=ref,event=branch,suffix=-${{ github.sha }}
+          type=sha,format=long
+          type=raw,value=latest,enable=${{ github.ref == format('refs/heads/{0}', 'main') }}
+
+    - name: Build and push
+      uses: docker/build-push-action@v6
+      with:
+        context: .
+        platforms: linux/amd64
+        push: true
+        tags: ${{ steps.meta.outputs.tags }}
+        labels: ${{ steps.meta.outputs.labels }}