Docker para rodar uma aplicação node

docker-compose.yml

version: '3'

services:
    app:
        build: .
        command: npm start
        ports: 
            - "3000:3000"
        volumes:
            - .:/usr/app

Dockerfile

FROM node:alpine 

WORKDIR /usr/app

COPY package.json ./
RUN npm install

COPY . .

EXPOSE 3000

CMD [ "npm", "start" ]