Add docker build workflow

.forgejo/workflows/docker.yaml

@@ -0,0 +1,26 @@
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  docker:
+    runs-on: ubuntu-22.04
+    steps:
+      # - run: "echo reg: ${{ env.GITHUB_SERVER_URL }}, act: ${{ github.actor }}, sec: ${{ github.token }}"
+      - name: Login to Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.GITHUB_SERVER_URL }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.REG_TOKEN }}
+      # -
+      #   name: Set up QEMU
+      #   uses: docker/setup-qemu-action@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          tags: git.mstar.dev/${{ env.GITHUB_REPOSITORY }}:latest