Speedup docker

docker-compose.yml

version: '2'
services:
  db:
    image: postgres:9.6.5-alpine
    volumes:
      - postgres-data:/var/lib/postgresql/data
  backend:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    ports:
      - "3000:3000"
    depends_on:
      - db
      - redis
    volumes:
      - .:/app
      - bundle:/bundle
    environment:
      - REDIS_URL=redis://redis:6379
  redis:
    image: redis:4.0.2-alpine
    ports:
      - "6379:6379"
    volumes:
      - redis-data:/var/lib/redis
    command: redis-server

volumes:
  postgres-data:
    driver: local
  redis-data:
    driver: local
  bundle:
    driver: local

docker-compose_old.yml

version: '2'
services:
  db:
    image: postgres:9.6.5-alpine
  backend:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    ports:
      - "3000:3000"
    depends_on:
      - db
      - redis
    environment:
      - REDIS_URL=redis://redis:6379
  redis:
    image: redis:4.0.2-alpine
    ports:
      - "6379:6379"
    command: redis-server

Dockerfile

FROM ruby:2.4.1-alpine3.6

RUN apk add --update build-base libffi-dev libxml2-dev libxslt-dev postgresql-dev nodejs tzdata bash

ENV RAILS_ENV=production \
    APP_HOME=/app \
   
ENV BUNDLE_PATH /bundle

RUN mkdir -p $APP_HOME
WORKDIR $APP_HOME

RUN gem install bundler
COPY Gemfile* $APP_HOME/

COPY . $APP_HOME

EXPOSE 3000
CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]

Dockerfile_old

FROM ruby:2.4.1-alpine3.6

RUN apk add --update build-base libffi-dev libxml2-dev libxslt-dev postgresql-dev nodejs tzdata bash

ENV RAILS_ENV=production \
    APP_HOME=/app \
   
RUN mkdir -p $APP_HOME
WORKDIR $APP_HOME

COPY Gemfile* $APP_HOME/
RUN gem install bundler
RUN bundle install

COPY . $APP_HOME

EXPOSE 3000
CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]