DockerでRuby on Railsの開発環境を構築する

ERROR: Version in "./docker-compose.yml" is unsupported. You might be seeing this error because you're using the wrong Compose file version. Either specify a supported version (e.g "2.2" or "3.3") and place your service definitions under the `services` key, or omit the `version` key and place your service definitions at the root of the file to use version 1.
For more on the Compose file format versions, see https://docs.docker.com/compose/compose-file/

#イメージの指定
FROM ruby:2.7.0

# yarnのインストール
RUN apt-get update && apt-get install -y curl apt-transport-https wget && \
  curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - && \
  echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list && \
  apt-get update && apt-get install -y yarn

# Node.jsのインストール
RUN apt-get update -qq && apt-get install -y nodejs yarn

# コンテナ内に作業ディレクトリを作成
RUN mkdir /myapp
WORKDIR /myapp
# Gemfileをコンテナ内の/myapp/Gemfileにコピー
COPY Gemfile /myapp/Gemfile
COPY Gemfile.lock /myapp/Gemfile.lock
# gemをインストール
RUN bundle install
# build contexのルートディレクトリをコンテナの/myappにコピー
COPY . /myapp

# Add a script to be executed every time the container starts.
COPY entrypoint.sh /usr/bin/
RUN chmod +x /usr/bin/entrypoint.sh
ENTRYPOINT ["entrypoint.sh"]
# ポート3000をリッスン
EXPOSE 3000

# Start the main process.
CMD ["rails", "server", "-b", "0.0.0.0"]

source 'https://rubygems.org'
gem 'rails', '6.0.3'

#!/bin/bash
set -e

# Remove a potentially pre-existing server.pid for Rails.
rm -f /myapp/tmp/pids/server.pid

# Then exec the container's main process (what's set as CMD in the Dockerfile).
exec "$@"

version: "3"
services:
  db:
    image: mysql:5.7
    environment:
      MYSQL_ROOT_PASSWORD: password
      MYSQL_DATABASE: root
    ports:
      - "3306:3306"
    volumes:
      - ./tmp/db:/var/lib/mysql

  web:
    build: .
    command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
    volumes:
      - .:/myapp
    ports:
      - "3000:3000"
    depends_on:
      - db

docker-compose run web rails new . --force --no-deps --database=mysql

docker-compose build

#development:に追記
  host: db
  username: root
  password: password

#test:に追記
  host: db
  username: root
  password: password

docker-compose run web rails db:create

docker-compose run web rails webpacker:install

rails aborted!
Don't know how to build task 'webpacker:install' (See the list of available tasks with `rails --tasks`)

# Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
gem 'webpacker', '~> 4.0'

docker-compose up -d

[“entrypoint.sh”]: not found