CI: add action using treetrail-backend-ci

.forgejo/workflows/build-with-app-image.yaml

@@ -0,0 +1,35 @@
+on:
+  push:
+
+jobs:
+  build:
+    runs-on: container
+    container:
+      image: tiptop:5000/treetrail-backend-ci
+      volumes:
+      - "/root/.cache/uv:uv_cache"
+    services:
+      treetrail-database:
+        image: treetrail-database
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install dependencies (to uv's project environment)
+        run: uv sync --locked --no-dev --no-editable
+
+      - name: Run basic test (bootstrap)
+        run: pytest -s tests/basic.py
+
+      - name: Build container
+        uses: actions/buildah-build@v1
+        with:
+          image: treetrail-backend
+          #tags: foo # v1 ${{ github.sha }}
+          containerfiles: |
+            ./Containerfile.for_runner
+
+      - uses: actions/push-to-registry@v2
+        with:
+          registry: "docker://${{ vars.REPOSITORY }}"
+          image: treetrail-backend
+          tags: latest