change nil? to blank?

app/controllers/jobs_controller.rb

@@ -29,20 +29,20 @@ class JobsController < ApplicationController
   end
 
   def show
-    unless params[:city_id].nil?
+    unless params[:city_id].blank?
       @job_count = Job.where(city_id: params[:city_id]).count
       @jobs = Job.where(city_id: params[:city_id]).page params[:page]
       @search_conditions = "All jobs in #{City.find(params[:city_id]).name}"
     end
 
-    unless params[:category_id].nil?
+    unless params[:category_id].blank?
       @job_ids = JobCategory.where(category_id: params[:category_id]).select(:job_id)
       @job_count = Job.where(id: @job_ids).count
       @jobs = Job.where(id: @job_ids).page params[:page]
       @search_conditions = "All jobs in #{Category.find(params[:category_id]).name}"
     end
 
-    unless params[:company_id].nil?
+    unless params[:company_id].blank?
       @job_count = Job.where(company_id: params[:company_id]).count
       @jobs = Job.where(company_id: params[:company_id]).page params[:page]
       @search_conditions = "All jobs in #{Company.find(params[:company_id]).name}"