asset_policy.rb

class AssetPolicy < ApplicationPolicy
  # some code
  
  class MetricScope < Scope
    def resolve
      if superadmin?
        scope.all
      else
        scope.none
      end
    end
  end
end  

dashboard_controller.rb

class Admin::DashboardController < Admin::AdminController
  def index
    scope = AssetPolicy::MetricScope.new(current_user, Asset.not_edited.not_sold.visible).resolve
    @assets_quarter    = Metrics::Dashboard::Assets.new(start_datetime: @quarter_start, end_datetime: @quarter_end, scope: scope )

    scope = UserPolicy::MetricScope.new(current_user, User.where(role: :user)).resolve
    @investors_quarter = Metrics::Dashboard::Investors.new(start_datetime: @quarter_start, end_datetime: @quarter_end, scope: scope)

    scope = OfferPolicy::MetricScope.new(current_user, Offer).resolve
    @offers_quarter    = Metrics::Dashboard::Offers.new(start_datetime: @quarter_start, end_datetime: @quarter_end, scope: scope)
  end  
end