Add multiarch Dockerfile

Dockerfile.multiarch

@@ -0,0 +1,30 @@
+FROM --platform=$BUILDPLATFORM node:lts-alpine AS build
+
+WORKDIR /usr/src/app
+COPY . .
+
+# Replace prod with prod-min to exclude the optional dbms dependencies
+# and uncomment the needed one below to build a smaller Docker image.
+RUN npm run prod
+#RUN npm install --no-package-lock pg
+#RUN npm install --no-package-lock aws-sdk
+#RUN npm install --no-package-lock memcached
+#RUN npm install --no-package-lock mongodb
+#RUN npm install --no-package-lock ioredis
+#RUN npm install --no-package-lock rethinkdbdash
+
+FROM --platform=$TARGETPLATFORM node:lts-alpine
+RUN apk add --no-cache curl
+
+WORKDIR /app
+COPY --from=build /usr/src/app .
+
+ENV PORT=7777
+EXPOSE ${PORT}
+STOPSIGNAL SIGINT
+ENTRYPOINT [ "node", "server.js" ]
+
+HEALTHCHECK --interval=30s --timeout=5s --start-period=5s \
+    --retries=1 CMD curl -sS -o /dev/null localhost:${PORT} || exit 1
+
+CMD [ "npm", "start" ]