Add CI.

.github/workflows/ci.yaml

@@ -0,0 +1,36 @@
+name: plot-navigator
+
+on:
+  pull_request:
+    branches:
+      - "main"
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+
+    steps:
+
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      -
+        name: Cache Docker layers
+        uses: actions/cache@v4
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-buildx-
+
+      -
+        name: Build
+        id: docker_build
+        uses: docker/build-push-action@v5
+        with:
+          push: false
+