change logic N+1 query

app/controllers/cities_controller.rb

 class CitiesController < ApplicationController
+    VIETNAM = 1
+    FOREIGN = 0
   def index
-    @cities_vietnam = City.location(1)
-    @cities_international = City.location(0)
+    @cities_vietnam = City.location(VIETNAM)
+    @cities_international = City.location(FOREIGN)
   end
 end

app/models/job.rb

@@ -16,7 +16,7 @@ class Job < ApplicationRecord
   has_many :histories
   has_many :users, through: :histories
 
-  scope :limit_job, -> { limit(5).order(created_at: :desc) }
+  scope :limit_job, -> { includes(:cities, :company).order(created_at: :desc).limit(5) }
   scope :all_job, -> { all.order(created_at: :desc) }
 
   def convert_job