Rails5+Docker環境におけるActiverecord関連付け後マイグレーションのエラー



### クリニックとそこに勤務するスタッフのDB作成と関連付けを行う。
rails 5系
ruby 2.4.5
Docker
下記環境

```Dockerfile
FROM ruby:2.4.5
RUN apt-get update -qq && apt-get install -y build-essential nodejs
RUN mkdir /app
WORKDIR /app
COPY Gemfile /app/Gemfile
COPY Gemfile.lock /app/Gemfile.lock
RUN bundle install
COPY . /app
```

```Docker-compose.yml
version: '3'
services:
  web:
    build: .
    command: bundle exec rails s -p 3000 -b '0.0.0.0'
    volumes:
      - .:/app
    ports:
      - 3000:3000
    depends_on:
      - db
    tty: true
    stdin_open: true
  db:
    image: mysql:5.7
    volumes:
      - db-volume:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: hoge
volumes:
  db-volume:

```

として、Activerecordのテーブル関連付けを行っております。

まずは、staffテーブルを

```ターミナル 
docker-compose exec web bundle exec rails g model staff clinic:references staff_name:string password_digest:string
```
として作り、

```20200831164400_create_staffs.rb
class CreateStaffs < ActiveRecord::Migration[5.0]
  def change
    create_table :staffs do |t|
      t.references :clinic, foreign_key: true
      t.string :staff_name, null: false
      t.string :password_digest, null: false

      t.timestamps
    end
    #ユニークキー制約
    add_index　:staffs, :staff_name, unique: true
  end
end
```
外部キーとNN制約とUQ制約をつけました。

clinicテーブルとして

```
docker-compose run web bundle exec rails g model clinic clinic_name:string
```

```20200831161252_create_clinics.rb
class CreateClinics < ActiveRecord::Migration[5.0]
  def change
    create_table :clinics do |t|
      t.string :clinic_name, null: false

      t.timestamps
    end
    #ユニークキー制約
    add_index　:clinics, :clinic_name, unique: true
  end
end

```
同様に、外部キーとNN制約とUQ制約をつけた。

最終的に、
```ターミナル 
docker-compose run web bundle exec rails db:migrate
```
マイグレーションをすると、

```ターミナル 
e-s-mba:test_csv_app eishunsudo$ docker-compose exec web bundle exec rails db:migrate
== 20200831161252 CreateClinics: migrating ====================================
-- create_table(:clinics)
rails aborted!
StandardError: An error has occurred, all later migrations canceled:

Mysql2::Error: Table 'clinics' already exists: CREATE TABLE `clinics` (`id` int AUTO_INCREMENT PRIMARY KEY, `clinic_name` varchar(255) NOT NULL, `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL) ENGINE=InnoDB
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:120:in `_query'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:120:in `block in query'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:119:in `handle_interrupt'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:119:in `query'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in `block in execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_adapter.rb:590:in `block in log'
/usr/local/bundle/gems/activesupport-5.0.7.2/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_adapter.rb:583:in `log'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in `execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/mysql/database_statements.rb:31:in `execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract/schema_statements.rb:278:in `create_table'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:423:in `create_table'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:846:in `block in method_missing'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:815:in `block in say_with_time'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:815:in `say_with_time'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:835:in `method_missing'
/app/db/migrate/20200831161252_create_clinics.rb:3:in `change'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:789:in `exec_migration'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:773:in `block (2 levels) in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:772:in `block in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:771:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:951:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1232:in `block in execute_migration_in_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1302:in `ddl_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1231:in `execute_migration_in_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1203:in `block in migrate_without_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1202:in `each'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1202:in `migrate_without_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1150:in `block in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1319:in `with_advisory_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1150:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1006:in `up'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:984:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/tasks/database_tasks.rb:163:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/rake_proxy.rb:14:in `block in run_rake_task'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/rake_proxy.rb:11:in `run_rake_task'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands.rb:18:in `<top (required)>'
/app/bin/rails:9:in `require'
/app/bin/rails:9:in `<top (required)>'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/rails.rb:28:in `load'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/rails.rb:28:in `call'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/command.rb:7:in `call'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client.rb:30:in `run'
/usr/local/bundle/gems/spring-2.1.1/bin/spring:49:in `<top (required)>'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/binstub.rb:11:in `load'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/binstub.rb:11:in `<top (required)>'
/app/bin/spring:15:in `require'
/app/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'

Caused by:
ActiveRecord::StatementInvalid: Mysql2::Error: Table 'clinics' already exists: CREATE TABLE `clinics` (`id` int AUTO_INCREMENT PRIMARY KEY, `clinic_name` varchar(255) NOT NULL, `created_at` datetime NOT NULL, `updated_at` datetime NOT NULL) ENGINE=InnoDB
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:120:in `_query'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:120:in `block in query'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:119:in `handle_interrupt'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:119:in `query'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in `block in execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_adapter.rb:590:in `block in log'
/usr/local/bundle/gems/activesupport-5.0.7.2/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_adapter.rb:583:in `log'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in `execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/mysql/database_statements.rb:31:in `execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract/schema_statements.rb:278:in `create_table'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:423:in `create_table'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:846:in `block in method_missing'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:815:in `block in say_with_time'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:815:in `say_with_time'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:835:in `method_missing'
/app/db/migrate/20200831161252_create_clinics.rb:3:in `change'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:789:in `exec_migration'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:773:in `block (2 levels) in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:772:in `block in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:771:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:951:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1232:in `block in execute_migration_in_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1302:in `ddl_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1231:in `execute_migration_in_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1203:in `block in migrate_without_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1202:in `each'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1202:in `migrate_without_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1150:in `block in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1319:in `with_advisory_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1150:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1006:in `up'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:984:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/tasks/database_tasks.rb:163:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/rake_proxy.rb:14:in `block in run_rake_task'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/rake_proxy.rb:11:in `run_rake_task'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands.rb:18:in `<top (required)>'
/app/bin/rails:9:in `require'
/app/bin/rails:9:in `<top (required)>'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/rails.rb:28:in `load'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/rails.rb:28:in `call'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/command.rb:7:in `call'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client.rb:30:in `run'
/usr/local/bundle/gems/spring-2.1.1/bin/spring:49:in `<top (required)>'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/binstub.rb:11:in `load'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/binstub.rb:11:in `<top (required)>'
/app/bin/spring:15:in `require'
/app/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'

Caused by:
Mysql2::Error: Table 'clinics' already exists
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:120:in `_query'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:120:in `block in query'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:119:in `handle_interrupt'
/usr/local/bundle/gems/mysql2-0.4.10/lib/mysql2/client.rb:119:in `query'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in `block in execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_adapter.rb:590:in `block in log'
/usr/local/bundle/gems/activesupport-5.0.7.2/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_adapter.rb:583:in `log'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in `execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/mysql/database_statements.rb:31:in `execute'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract/schema_statements.rb:278:in `create_table'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:423:in `create_table'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:846:in `block in method_missing'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:815:in `block in say_with_time'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:815:in `say_with_time'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:835:in `method_missing'
/app/db/migrate/20200831161252_create_clinics.rb:3:in `change'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:789:in `exec_migration'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:773:in `block (2 levels) in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:772:in `block in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in `with_connection'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:771:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:951:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1232:in `block in execute_migration_in_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1302:in `ddl_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1231:in `execute_migration_in_transaction'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1203:in `block in migrate_without_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1202:in `each'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1202:in `migrate_without_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1150:in `block in migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1319:in `with_advisory_lock'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1150:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:1006:in `up'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/migration.rb:984:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/tasks/database_tasks.rb:163:in `migrate'
/usr/local/bundle/gems/activerecord-5.0.7.2/lib/active_record/railties/databases.rake:58:in `block (2 levels) in <top (required)>'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/rake_proxy.rb:14:in `block in run_rake_task'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/rake_proxy.rb:11:in `run_rake_task'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:51:in `run_command!'
/usr/local/bundle/gems/railties-5.0.7.2/lib/rails/commands.rb:18:in `<top (required)>'
/app/bin/rails:9:in `require'
/app/bin/rails:9:in `<top (required)>'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/rails.rb:28:in `load'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/rails.rb:28:in `call'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client/command.rb:7:in `call'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/client.rb:30:in `run'
/usr/local/bundle/gems/spring-2.1.1/bin/spring:49:in `<top (required)>'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/binstub.rb:11:in `load'
/usr/local/bundle/gems/spring-2.1.1/lib/spring/binstub.rb:11:in `<top (required)>'
/app/bin/spring:15:in `require'
/app/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)
e-s-mba:test_csv_app eishunsudo$
```

となりった。
これはマイグレーションは成功しているのか？
[rails db:migrateした際のエラー文 Index name ○○ on table テーブル名 already existsの解決法](https://qiita.com/shota0701nemoto/items/b1158caebe3788eb39c8)
この前に、Index〜〜のエラーがでたが、ここらへんにヒントがあるかもしれない、、、

[docker-composeでMySQL5.7を起動して接続してみた](https://qiita.com/LazyHippos/items/58d0f98a15656ed65136)
mysqlに接続すれば、確認できるのだろうか？