A relation issue after switching from sqlite3 to Postgres

I get this error when trying to access index#bills page:

ActiveRecord::StatementInvalid in BillsController#index
PG::UndefinedTable: ERROR: relation "bills" does not exist LINE 5: 
WHERE a.attrelid = '"bills"'::regclass ^ : SELECT a.attname, format_type(a.atttypid, a.atttypmod), pg_get_expr(d.adbin, d.adrelid), 
a.attnotnull, a.atttypid, a.atttypmod FROM pg_attribute a LEFT JOIN 
pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum WHERE 
a.attrelid = '"bills"'::regclass AND a.attnum > 0 AND NOT a.attisdropped 
ORDER BY a.attnum

I followed this guide on how to switch from Sqlite3 to Postgres: http://ift.tt/1hLgdWz

Here are some info about my app:

1. I have three models, Property, bill and resident. I can access the index page of both resident and property and I can create new property and edit it but not with bills.
2. this issue appeared after the switching. It was working fine before switching to Postgres.

3. this is how my database.yml look like:

   development:
     adapter: postgresql
     encoding: unicode
     database: demo_test_development
     pool: 5
     username: 
     password:
     timeout: 5000
   
   test:
     adapter: postgresql
     encoding: unicode
     database: demo_test_test
     pool: 5
     username: 
     password:
     timeout: 5000
   
   production:
     adapter: postgresql
     encoding: utf8
     database: demo_test_production
     pool: 5
     username: 
     password:
   
   

4. my models:

   class Bill < ActiveRecord::Base
     belongs_to :property
     belongs_to :user
     belongs_to :resident
     has_many :photos
   end
   
   class Property < ActiveRecord::Base
     belongs_to :user
     has_many :photos
     has_one :resident
     has_many :bills    
     validate :address , :city , :country
   end
   
   class Resident < ActiveRecord::Base
       belongs_to :user
       has_many :photos
       has_one :property
       has_many :bills  
       validates_presence_of :name
   end
   
   

5. and this is my BillsController where it show the error:

   class BillsController < ApplicationController
     before_action :set_bill, only: [:show, :edit, :update]
     before_action :authenticate_user!
   
     def index
       @bills = current_user.bills
     end
   
     def show
       @bill = Bill.find(params[:id])
       @photos = @bill.photos
   
     end
   
     def new
       @bill = current_user.bills.build
     end
   
     def create
       @bill = current_user.bills.build(bill_params)
       if @bill.save
         if params[:images]
           params[:images].each do |image|
             @bill.photos.create(image: image)
           end
         end
   
         @photos = @bill.photos
         redirect_to edit_bill_path(@bill), notice: "Saved"
       else
         render :new
       end
     end
   
     def edit
       if current_user.id == @bill.user.id
         @photos = @bill.photos
       else
         redirect_to root_path, notice: "You don't have access to this page"
       end
     end
   
     def update
       if @bill.update(bill_params)
         if params[:images]
           params[:images].each do |image|
             @bill.photos.create(image: image)
           end
         end
   
         redirect_to edit_bill_path(@bill), notice: "Updated"
       else
         render :edit
       end
     end
   
     private
   
     def set_bill
       @bill = Bill.find(params[:id])
     end
   
     def bill_params
       params.require(:bill).permit(:due_date, :amount, :bill_type, :bill_status, :description, :property_id, :resident_id)
     end
   end