ci: add mirror job to push to GitHub

.gitea/workflows/ci.yml

@@ -187,3 +187,26 @@ jobs:
             ${TAGS} \
             .
 # Test 1765481480
+
+  mirror:
+    name: Mirror to GitHub
+    runs-on: ubuntu-latest
+    needs: [test, lint]
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main' && vars.MIRROR_ENABLED != 'false'
+    container:
+      image: debian:bookworm-slim
+      volumes:
+        - /root/.ssh:/root/.ssh:ro
+    steps:
+      - name: Install git
+        run: apt-get update && apt-get install -y --no-install-recommends git openssh-client ca-certificates && rm -rf /var/lib/apt/lists/*
+
+      - name: Clone and mirror
+        env:
+          GIT_SSH_COMMAND: "ssh -i /root/.ssh/id_ed25519 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no"
+        run: |
+          git config --global --add safe.directory "$GITHUB_WORKSPACE"
+          git clone --mirror ${{ env.GITEA_URL }}/${GITHUB_REPOSITORY}.git repo.git
+          cd repo.git
+          git remote add github git@github.com:PlusOne/dbbackup.git
+          git push --mirror github || git push --force --all github && git push --force --tags github