development環境で"fe_sendauth: no password supplied"が発生する

Question

前提・実現したいこと

[前提]
速習実践ガイドでRuby on Railsを勉強しています。
"bin/rails s"をdevelopment環境で行ったときにブラウザ上で"fe_sendauth: no password supplied"というエラーが発生します。
昨日はこのようなエラーはでなくて今日突然development環境でエラーが発生しました。
昨日production環境用のデータベースやproduction環境用のユーザを作成したことが影響しているかもしれません。昨日はそのあとでもdevelopment環境でエラーがでなかったのですが。。

[実現したいこと]
エラーを改善してdevelopment環境で開発したい。

[開発環境]
・ubuntu20.04
・ruby2.5.1
・rails 5.2.4.4
・postgresql 12.4

発生している問題・エラーメッセージ

boko@DESKTOP-FS4FC62:~/Code/taskleaf2$ bin/rails s
=> Booting Puma
=> Rails 5.2.4.4 application starting in development 
=> Run `rails server -h` for more startup options
Puma starting in single mode...
* Version 3.12.6 (ruby 2.5.1-p57), codename: Llamas in Pajamas
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://localhost:3000
Use Ctrl-C to stop
Started GET "/" for ::1 at 2020-09-14 17:05:53 +0900
  
PG::ConnectionBad (fe_sendauth: no password supplied
):

該当のソースコード

↓"database.yml"です。"."の入力方向が分かりませんでした。

# PostgreSQL. Versions 9.1 and up are supported.
#
# Install the pg driver:
#   gem install pg
# On OS X with Homebrew:
#   gem install pg -- --with-pg-config=/usr/local/bin/pg_config
# On OS X with MacPorts:
#   gem install pg -- --with-pg-config=/opt/local/lib/postgresql84/bin/pg_config
# On Windows:
#   gem install pg
#       Choose the win32 build.
#       Install PostgreSQL and put its /bin directory on your path.
#
# Configure Using Gemfile
# gem 'pg'
#
default: &default
  adapter: postgresql
  encoding: unicode
  # For details on connection pooling, see Rails configuration guide
  # http://guides.rubyonrails.org/configuring.html#database-pooling
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

development:
  <<: *default
  database: taskleaf2_development

  # The specified database role being used to connect to postgres.
  # To create additional roles in postgres see `$ createuser --help`.
  # When left blank, postgres will use the default role. This is
  # the same name as the operating system user that initialized the database.
  #username: taskleaf2

  # The password associated with the postgres role (username).
  #password:

  # Connect on a TCP socket. Omitted by default since the client uses a
  # domain socket that doesn't need configuration. Windows does not have
  # domain sockets, so uncomment these lines.
  #host: localhost

  # The TCP port the server listens on. Defaults to 5432.
  # If your server runs on a different port number, change accordingly.
  #port: 5432

  # Schema search path. The server defaults to $user,public
  #schema_search_path: myapp,sharedapp,public

  # Minimum log levels, in increasing order:
  #   debug5, debug4, debug3, debug2, debug1,
  #   log, notice, warning, error, fatal, and panic
  # Defaults to warning.
  #min_messages: notice

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: taskleaf2_test

# As with config/secrets.yml, you never want to store sensitive information,
# like your database password, in your source code. If your source code is
# ever seen by anyone, they now have access to your database.
#
# Instead, provide the password as a unix environment variable when you boot
# the app. Read http://guides.rubyonrails.org/configuring.html#configuring-a-database
# for a full rundown on how to provide these environment variables in a
# production deployment.
#
# On Heroku and other platform providers, you may have a full connection URL
# available as an environment variable. For example:
#
#   DATABASE_URL="postgres://myuser:mypass@localhost/somedatabase"
#
# You can use this database configuration with:
#
#   production:
#     url: <%= ENV['DATABASE_URL'] %>
#
production:
  <<: *default
  database: taskleaf2_production
  username: taskleaf2
  password: <%= ENV['TASKLEAF2_DATABASE_PASSWORD'] %>

↓"pg_hba.conf"です。

# Database administrative login by Unix domain socket
local   all             postgres                                peer

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     md5
# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
# IPv6 local connections:
host    all             all             ::1/128                 md5
# Allow replication connections from localhost, by a user with the
# replication privilege.
local   replication     all                                     peer
host    replication     all             127.0.0.1/32            md5
host    replication     all             ::1/128                 md5

試したこと

"database.yml"のdevelopment環境の欄に以下のようにパスワードをセットしてみたところ

~~~
development:
  <<: *default
  database: taskleaf2_development
  username: taskleaf2
  password: <%= ENV['TASKLEAF2_DATABASE_PASSWORD'] %>
~~~

以下のような異なるエラーが発生しました。なので上記の変更は取り消しました。

boko@DESKTOP-FS4FC62:~/Code/taskleaf2$ bin/rails s
=> Booting Puma
=> Rails 5.2.4.4 application starting in development 
=> Run `rails server -h` for more startup options
Puma starting in single mode...
* Version 3.12.6 (ruby 2.5.1-p57), codename: Llamas in Pajamas
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://localhost:3000
Use Ctrl-C to stop
Started GET "/" for ::1 at 2020-09-14 17:21:30 +0900
   (2.7ms)  SELECT "schema_migrations"."version" FROM "schema_migrations" ORDER BY "schema_migrations"."version" ASC
  ↳ /home/boko/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.4.4/lib/active_record/log_subscriber.rb:98
  
ActiveRecord::StatementInvalid (PG::InsufficientPrivilege: ERROR:  permission denied for table schema_migrations
: SELECT "schema_migrations"."version" FROM "schema_migrations" ORDER BY "schema_migrations"."version" ASC):

補足情報（FW/ツールのバージョンなど）

今まで特にdevelopment環境においてパスワードで弾かれたことはなかったのに、development環境で弾かれるようになりました。development環境で弾かれることはあるのでしょうか？

どのような些細なことでも回答やコメントしていただけると嬉しいです。

Answer 1

"pg_hba.conf"を以下のように変更したら解決しました。

# "local" is for Unix domain socket connections only
local   all             all                                     peer