improve ShippingMethod#includes? n+1 query
improve ShippingMethod#includes? n+1 query

ayb/spree,calvinl/spree,imella/spree,DarkoP/spree,vinsol/spree,calvinl/spree,vinsol/spree,DarkoP/spree,siddharth28/spree,vinsol/spree,imella/spree,DarkoP/spree,vinayvinsol/spree,calvinl/spree,siddharth28/spree,brchristian/spree,DarkoP/spree,vinayvinsol/spree,brchristian/spree,ayb/spree,vinayvinsol/spree,calvinl/spree,brchristian/spree,ayb/spree,ayb/spree,brchristian/spree,siddharth28/spree,siddharth28/spree,imella/spree,vinsol/spree,vinayvinsol/spree