parameters.rb

    def require(key)
      self[key].presence || raise(ActionController::ParameterMissing.new(key))
    end

    alias :required :require

    def permit(*filters)
      params = self.class.new

      filters.each do |filter|
        case filter
        when Symbol, String
          permitted_scalar_filter(params, filter)
        when Hash then
          hash_filter(params, filter)
        end
      end

      unpermitted_parameters!(params) if self.class.action_on_unpermitted_parameters

      params.permit!
    end