【 Ruby on Rails 】自分のFlash message をカスタムする

app/controllers/application_controller.rb

class ApplicationController
  add_flash_types :good, :bad
end

app/controllers/users_controller.rb

class UsersController < ApplicationController
  def create
    redirect_to root_path, good: "Created user!"
  end
end

app/views/users/index.html.erb

<%= good %>