build: add docker CI

.gitea/workflows/ci.yml

@@ -14,3 +14,21 @@ jobs:
       - run: bun test
         env:
           DATABASE_URL: ${{ secrets.DATABASE_URL }}
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Login to Registry
+        uses: docker/login-action@v2
+        with:
+          registry: {{ registry_url }}
+          username: {{ secrets.DOCKER_USERNAME }}
+          password: {{ secrets.DOCKER_TOKEN }}
+      - uses: actions/checkout@v4
+      - uses: docker/setup-buildx-action@v2
+      - name: Build image
+        uses: docker/build-push-action@v4.2.1
+        with:
+          context: .
+          push: true
+          tags: {{ registry_url }}trafficcue/trafficcue-server:latest
+          platforms: linux/amd64