ActionMailer

実際に送らずに送る内容をブラウザで確認

・ryanb/letter_opener

Rails4

・Rails - ActionMailerのテスト - Qiita [キータ]

SMTPで送る

ActionMailer::Base.delivery_method = :sendmail

を

ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.smtp_settings = {
:address => "***.ne.jp",
:port => 25,
:authentication => :plain,
:user_name => "***@***ne.jp",
:password => '****'
}

にする