Add Rails.heroku_env (like Rails.env) to know in which heroku environment you are (Based on HEROKU_APP_NAME, that you can get from runtime-dyno-metadata labs plugin )

rails.rb

# config/initializers/rails.rb
# Based on Rails.env http://api.rubyonrails.org/classes/Rails.html#method-c-env
module Rails
  # Use runtime-dyno-metadata labs plugin. See https://devcenter.heroku.com/articles/dyno-metadata

  class << self
    def heroku_env
      if @_heroku_env
        @_heroku_env
      elsif ENV['HEROKU_APP_NAME']
        production_app_names = ['myapp-prod', 'myapp-beta']
        heroku_env = production_app_names.include?(ENV['HEROKU_APP_NAME']) ? 'production' : 'staging'
        @_heroku_env = ActiveSupport::StringInquirer.new(heroku_env)
      else
        @_heroku_env = ActiveSupport::StringInquirer.new('development')
      end
    end

    def heroku_env=(environment)
      @_heroku_env = ActiveSupport::StringInquirer.new(environment)
    end
  end
end