Build docker and publish docker image in CI

.forgejo/workflows/publish-docker.yml

@@ -0,0 +1,36 @@
+name: Publish Docker image
+
+on:
+  push:
+    branches:
+      - 'main'
+
+jobs:
+  push_to_registry:
+    name: Push Docker image to local registry
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v3
+        with:
+          submodules: recursive
+
+      - name: setup buildx
+        uses: https://github.com/docker/setup-buildx-action@v2
+
+      - name: Log in to local registry
+        run: |
+          BASE64_AUTH=`echo -n "$CI_REGISTRY_USER:$CI_REGISTRY_PASSWORD" | base64`
+          mkdir -p ~/.docker
+          echo "{\"auths\": {\"$CI_REGISTRY\": {\"auth\": \"$BASE64_AUTH\"}}}" > ~/.docker/config.json        
+        env:
+          CI_REGISTRY: https://git.kallestruik.nl
+          CI_REGISTRY_USER: ${{ secrets.FORGEJO_USERNAME }}
+          CI_REGISTRY_PASSWORD: ${{ secrets.FORGEJO_PASSWORD }}
+
+      - name: Build and push Docker image
+        uses: https://github.com/docker/build-push-action@v4
+        with:
+          context: .
+          push: true
+          tags: "git.kallestruik.nl/kalle/esl-docker:latest"