Postgres データベースの接続に問題があります。そのためのユーザーを作成しました（パスワードの入力を求められることはありませんでした）ので、コマンドALTER USER user_name WITH PASSWORD passwordを実行して作成しました。database.ymlRails プロジェクトの config ディレクトリにあるファイルにユーザーとパスワードを設定しました。認証に失敗した (タイトルのように) というメッセージが表示されますが、その理由はわかりません。このリンクpg_hba.confのこの回答からファイルを変更しました。この問題を解決する唯一の方法は、ユーザーをスーパーユーザーにすることです。しかし、スーパーユーザーにしないとこれが機能しない理由を知りたいです。誰でも何か考えがありますか？
編集：
=> Booting Thin
=> Rails 3.2.11 application starting in production on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `initialize': FATAL: password authentication failed for user "crowdcode" (PG::Error)
FATAL: password authentication failed for user "crowdcode"
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `new'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `connect'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:326:in `initialize'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:308:in `clear_cache!'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activerecord-3.2.11/lib/active_record/railtie.rb:97:in `block (2 levels) in <class:Railtie>'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:418:in `_run__898392718112352949__prepare__1631078305261036285__callbacks'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:405:in `__run_callback'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:385:in `_run_prepare_callbacks'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:81:in `run_callbacks'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/actionpack-3.2.11/lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/actionpack-3.2.11/lib/action_dispatch/middleware/reloader.rb:48:in `prepare!'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/application/finisher.rb:47:in `block in <module:Finisher>'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `instance_exec'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `run'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/initializable.rb:55:in `block in run_initializers'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `each'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `run_initializers'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/application.rb:136:in `initialize!'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /home/ubuntu/Git/crowdcode/config/environment.rb:5:in `<top (required)>'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `block in require'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
from /home/ubuntu/Git/crowdcode/config.ru:3:in `block in <main>'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
from /home/ubuntu/Git/crowdcode/config.ru:in `new'
from /home/ubuntu/Git/crowdcode/config.ru:in `<main>'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/commands/server.rb:46:in `app'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/commands/server.rb:70:in `start'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/commands.rb:55:in `block in <top (required)>'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/commands.rb:50:in `tap'
from /home/ubuntu/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/railties-3.2.11/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'