add workflow

.gitea/workflows/build.yaml

@@ -0,0 +1,25 @@
+name: Build and push Docker image
+on: push
+#  pull_request:
+#    types:
+#      - closed
+#    branches:
+#      - main
+jobs:
+  build:
+    runs-on: remote
+    steps:
+      - name: Checkout
+        uses: https://git.simonis.lol/actions/checkout@v4
+
+      - name: Build
+        run: docker buildx build -f .docker/Dockerfile -t git.simonis.lol/projects/casino-frontend:latest .
+
+      - name: Login
+        uses: https://git.simonis.lol/actions/login@v1
+        with:
+          registry: git.simonis.lol
+          username: ${{ vars.DOCKER_USER }}
+          password: ${{ vars.DOCKER_PW }}
+      - name: Push
+        run: docker push git.simonis.lol/projects/casino-frontend:latest