Add simple CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,15 @@
+name: ci
+
+on:
+    push:
+
+jobs:
+    docker:
+        runs-on: ubuntu-latest
+        steps:
+            - name: Setup Docker Buildx
+              uses: docker/setup-buildx-action@v3
+
+            - name: Build image
+              run: |
+                ./scripts/update.sh