add support for docker deployments

.github/workflows/main.yml

@@ -0,0 +1,23 @@
+name: Publish a new Docker image
+
+on:
+  push:
+    branches: [master]
+
+jobs:
+  build-and-publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-qemu-action@v3
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - uses: docker/build-push-action@v5
+        with:
+          push: true
+          context: .
+          platforms: linux/amd64,linux/arm64
+          tags: chrissx/jana:latest

Dockerfile

@@ -0,0 +1,15 @@
+FROM dart:stable AS build
+
+WORKDIR /app
+COPY pubspec.yaml .
+RUN dart pub get
+COPY bin ./bin
+RUN dart compile exe bin/jana.dart -o bin/app
+
+FROM scratch
+COPY --from=build /runtime/ /
+COPY --from=build /app/bin/app /app/bin/
+
+ENV JANA_DISCORD_TOKEN=
+
+CMD ["/app/bin/app"]