docker-compose and Dockerfile for RoR environment

docker-compose.yml

version: '3'
volumes:
  mysql-data:
services:
  db:
    image: mysql:5.7
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    volumes:
      - "mysql-data:/var/lib/mysql"
    environment:
      MYSQL_ROOT_PASSWORD: root
  web:
    build: .
    command: bash -c "bundle exec rails s -p 3000 -b 0.0.0.0"
    volumes:
      - .:/app
    ports:
      - "3000:3000"
    links:
      - db
    depends_on:
      - db
    environment: 
      DB_USER: root
      DB_NAME: site_sefin
      DB_PASSWORD: root
      DB_HOST: db

Dockerfile

FROM ruby:2.6

RUN apt-get update -qq && apt-get install -y nodejs
RUN mkdir /app

WORKDIR /app

COPY Gemfile /app/Gemfile
COPY Gemfile.lock /app/Gemfile.lock

RUN bundle install

COPY . /app