ci: add container build

.gitea/workflows/ci.yaml

@@ -0,0 +1,28 @@
+name: Container build
+on: [ push ]
+
+jobs:
+  container-build:
+    runs-on: ubuntu-latest
+    if: gitea.ref == 'refs/heads/main'
+    steps:
+      - name: Clone repo
+        uses: actions/checkout@v4
+      - name: Set up BuildX
+        uses: docker/setup-buildx-action@v2
+        with:
+          endpoint: 'unix:///var/run/docker.sock'
+      - name: Login to Registry
+        uses: docker/login-action@v3
+        with:
+          registry: git.plabble.org
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+      - name: Build and push
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          file: ./Containerfile
+          push: true
+          tags: |
+            git.plabble.org/job79/dev:latest