add build workflow

.gitea/workflows/build.yaml

@@ -0,0 +1,14 @@
+name: Test build
+run-name: ${{ gitea.event_name }} is testing out Gitea Actions 🚀
+on: [push]
+
+jobs:
+  Build-Docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository code
+        uses: actions/checkout@v4
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Build Docker Image
+        run: docker buildx build -t ${{ vars.DOCKER_TAG }} .