optimize code

app/models/job.rb

@@ -9,7 +9,6 @@ class Job < ApplicationRecord
 
   def self.create_new_jobs(arr_jobs)
     arr_jobs.each do |item|
-      job_cities = []
       city_names = []
       job_industries = []
       industry_names = []
@@ -24,27 +23,26 @@ class Job < ApplicationRecord
       # City
       unless item[:city].blank?
         city_names = item[:city].split(',').map(&:strip)
-
-        job_cities = City.where(name: city_names)
-        job_cities.each do |city|
-          job.cities << city
-        end
+        job.cities << City.where(name: city_names)
       end
 
       # Company
-      job.company = Company.find_or_create_by(name: item[:company_name])
-      job.company.location = item[:company_location]
-      job.company.description = item[:company_description]
+       company = Company.find_by(name: item[:company_name])
+      job.company =
+      if company.nil?
+        Company.create(name: item[:company_name],
+                                 location: item[:company_location],
+                                 description: item[:company_description])
+      else
+        company
+      end
       job.company.cities = job.cities
 
       # Industry
       unless item[:industry].blank?
         industry_names = item[:industry].split(',').map(&:strip)
         job_industries = Industry.where(name: industry_names)
-
-        job_industries.each do |industry|
-          job.industries << industry
-        end
+        job.industries << job_industries
 
         industry_names = industry_names - job_industries.pluck(:name)
         industry_names.each do |name|

db/migrate/20171005084200_create_join_table_jobs_cites.rb

 class CreateJoinTableJobsCites < ActiveRecord::Migration[5.1]
   def change
-    create_join_table :jobs_cities do |t|
+    create_table :cities_jobs do |t|
       t.references :job, index: true
       t.references :city, index: true
     end

db/migrate/20171005085453_create_join_table_cities_companies.rb

 class CreateJoinTableCitiesCompanies < ActiveRecord::Migration[5.1]
   def change
-    create_join_table :cities_companies, id: false do |t|
+    create_table :cities_companies, id: false do |t|
       t.references :company, index: true
       t.references :city, index: true
     end