update ActiveRecord -- RecordNotFound handle

app/controllers/application_controller.rb

 class ApplicationController < ActionController::Base
+  rescue_from ActiveRecord::RecordNotFound, with: :record_not_found
+
+  protected
+
+  def record_not_found
+    respond_to do |format|
+      format.html { render file: "#{Rails.root}/public/404",
+                           layout: false,
+                           status: :not_found }
+      format.xml  { head :not_found }
+      format.any  { head :not_found }
+    end
+  end
 end

app/controllers/jobs_controller.rb

 # frozen_string_literal: true
 
 class JobsController < ApplicationController
-  # rescue_from ActiveRecord::RecordNotFound, with: :job_not_found
+
   def index
-      search_str  = params[:search].blank? ? '*' : params[:search]
-      job_found = Job.search(kw: search_str, page: params[:page].to_i)
-      @job_ids  = job_found[:job_id]
-      @job_num = job_found[:num]
-      job_search_result = Job.where(id: @job_ids)
+      search_str = params[:search].blank? ? '*' : params[:search]
+      job_found  = Job.search(kw: search_str, page: params[:page].to_i)
+      job_ids   = job_found[:job_id]
+      @job_num   = job_found[:num]
+      job_search_result = Job.where(id: job_ids)
       @jobs = Kaminari.paginate_array(job_search_result,
                                       total_count: @job_num).
-                       page(params[:page]).
-                       per(Kaminari.config.default_per_page)
-
+                       page(params[:page])
   end
 
   def show
-    @job = Job.find_by(id: params[:id])
-    unless @job.nil?
-      return @job
-    else
-      job_not_found(params[:id])
-    end
+    @job = Job.find(params[:id])
   end
 
   def city
@@ -37,9 +30,4 @@ class JobsController < ApplicationController
     @jobs = Job.all.order(updated_at: :desc).take(5)
     @cities = City.all.select { |city| city.jobs.any? }.take(8)
   end
-
-  def job_not_found(id)
-    redirect_to root_path
-    flash[:danger] = "Couldn't find job id: #{id}"
-  end
 end

app/models/job.rb

 # frozen_string_literal: true
 
 class Job < ApplicationRecord
-  attr_accessor :page_per
   belongs_to :company, foreign_key: 'company_id'
 
   has_many :cities_jobs,  foreign_key: 'job_id',
@@ -34,8 +33,6 @@ class Job < ApplicationRecord
   validates :condition, presence: true, length: { maximum: 1000 }
   validates :link, presence: true
 
-  @page_per = 10
-  paginates_per @page_per
 
   def self.search(search_hash = { kw: '*', page: 0})
     jobs = { job_id: [], job_num: 0 }