Bill#update_date_paid method not found?

bill.rb

#app/models/bill.rb

class Bill < ActiveRecord::Base
  belongs_to :customer
  attr_accessible :amount, :date_due, :paid
  before_create :default_values
  before_save self.update_date_paid

  def default_values
    self.paid ||= false
  end

  def self.find_pending
    where(:paid => false)
  end

  def self.find_paid
    where(:paid => true)
  end

  def self.update_date_paid
    if self.paid && self.date_paid.nil?
      write_attribute(:date_paid, Time.now)
    elsif self.paid == false && !self.date_paid.nil?
      write_attribute(:date_paid, nil)
    end
  end
end
# == Schema Information
#
# Table name: bills
#
#  id          :integer         not null, primary key
#  customer_id :integer
#  amount      :integer
#  date_paid   :datetime
#  paid        :boolean
#  created_at  :datetime        not null
#  updated_at  :datetime        not null
#  date_due    :date
#

bill_controller.rb

#app/controllers/bills_controller.rb

class BillsController < ApplicationController
  # GET /bills/new
  # GET /bills/new.json
  def new
    @bill = Bill.new
    @customer = Customer.find(params[:customer_id])

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @bill }
    end
  end

  # GET /bills/1/edit
  def edit
    @bill = Bill.find(params[:id])
    @customer = Customer.find(@bill.customer_id)
  end

  # POST /bills
  # POST /bills.json
  def create
    @customer = Customer.find(params[:customer_id])
    @bill = @customer.bills.build(params[:bill])

    respond_to do |format|
      if @bill.save
        format.html { redirect_to @customer, notice: 'Bill was successfully created.' }
        format.json { render json: @bill, status: :created, location: @bill }
      else
        format.html { render action: "new" }
        format.json { render json: @bill.errors, status: :unprocessable_entity }
      end
    end
  end

  # PUT /bills/1
  # PUT /bills/1.json
  def update
    @bill = Bill.find(params[:id])
    @customer = Customer.find(@bill.customer_id)

    respond_to do |format|
      if @bill.update_attributes(params[:bill])
        format.html { redirect_to @customer, notice: 'Bill was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: "edit" }
        format.json { render json: @bill.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /bills/1
  # DELETE /bills/1.json
  def destroy
    @bill = Bill.find(params[:id])
    @bill.destroy

    respond_to do |format|
      format.html { redirect_to :back }
      format.json { head :no_content }
    end
  end
end

customers_controller.rb

#app/controllers/customers_controller.rb

class CustomersController < ApplicationController
  # GET /customers
  # GET /customers.json
  def index
    @customers = Customer.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { render json: @customers }
    end
  end

  # GET /customers/1
  # GET /customers/1.json
  def show
    @customer = Customer.find(params[:id])
    @phones = @customer.phones.find(:all)
    @emails = @customer.emails.find(:all)
    @pending_bills = @customer.bills.find_pending()
    @paid_bills = @customer.bills.find_paid()
    @notes = @customer.notes.find(:all)
    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @customer }
    end
  end

  # GET /customers/new
  # GET /customers/new.json
  def new
    @customer = Customer.new

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @customer }
    end
  end

  # GET /customers/1/edit
  def edit
    @customer = Customer.find(params[:id])
  end

  # POST /customers
  # POST /customers.json
  def create
    @customer = Customer.new(params[:customer])

    respond_to do |format|
      if @customer.save
        format.html { redirect_to @customer, notice: 'Customer was successfully created.' }
        format.json { render json: @customer, status: :created, location: @customer }
      else
        format.html { render action: "new" }
        format.json { render json: @customer.errors, status: :unprocessable_entity }
      end
    end
  end

  # PUT /customers/1
  # PUT /customers/1.json
  def update
    @customer = Customer.find(params[:id])

    respond_to do |format|
      if @customer.update_attributes(params[:customer])
        format.html { redirect_to @customer, notice: 'Customer was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: "edit" }
        format.json { render json: @customer.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /customers/1
  # DELETE /customers/1.json
  def destroy
    @customer = Customer.find(params[:id])
    @customer.destroy

    respond_to do |format|
      format.html { redirect_to customers_url }
      format.json { head :no_content }
    end
  end
end

error

http://localhost:3000/customers/1

NoMethodError in CustomersController#show

undefined method `update_date_paid' for #<Class:0x9f72a34>
Rails.root: /vagrant/billing

Application Trace | Framework Trace | Full Trace
activerecord (3.2.1) lib/active_record/dynamic_matchers.rb:50:in `method_missing'
app/models/bill.rb:5:in `<class:Bill>'
app/models/bill.rb:1:in `<top (required)>'
activesupport (3.2.1) lib/active_support/dependencies.rb:469:in `load'
activesupport (3.2.1) lib/active_support/dependencies.rb:469:in `block in load_file'
activesupport (3.2.1) lib/active_support/dependencies.rb:639:in `new_constants_in'
activesupport (3.2.1) lib/active_support/dependencies.rb:468:in `load_file'
activesupport (3.2.1) lib/active_support/dependencies.rb:353:in `require_or_load'
activesupport (3.2.1) lib/active_support/dependencies.rb:502:in `load_missing_constant'
activesupport (3.2.1) lib/active_support/dependencies.rb:192:in `block in const_missing'
activesupport (3.2.1) lib/active_support/dependencies.rb:190:in `each'
activesupport (3.2.1) lib/active_support/dependencies.rb:190:in `const_missing'
activesupport (3.2.1) lib/active_support/dependencies.rb:514:in `load_missing_constant'
activesupport (3.2.1) lib/active_support/dependencies.rb:192:in `block in const_missing'
activesupport (3.2.1) lib/active_support/dependencies.rb:190:in `each'
activesupport (3.2.1) lib/active_support/dependencies.rb:190:in `const_missing'
activesupport (3.2.1) lib/active_support/inflector/methods.rb:229:in `block in constantize'
activesupport (3.2.1) lib/active_support/inflector/methods.rb:228:in `each'
activesupport (3.2.1) lib/active_support/inflector/methods.rb:228:in `constantize'
activesupport (3.2.1) lib/active_support/dependencies.rb:554:in `get'
activesupport (3.2.1) lib/active_support/dependencies.rb:588:in `constantize'
activerecord (3.2.1) lib/active_record/inheritance.rb:111:in `block in compute_type'
activerecord (3.2.1) lib/active_record/inheritance.rb:109:in `each'
activerecord (3.2.1) lib/active_record/inheritance.rb:109:in `compute_type'
activerecord (3.2.1) lib/active_record/reflection.rb:172:in `klass'
activerecord (3.2.1) lib/active_record/associations/association.rb:117:in `klass'
activerecord (3.2.1) lib/active_record/associations/collection_proxy.rb:87:in `method_missing'
app/controllers/customers_controller.rb:19:in `show'
actionpack (3.2.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.1) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.1) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.1) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.1) lib/active_support/callbacks.rb:414:in `_run__373879947__process_action__6850445__callbacks'
activesupport (3.2.1) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.1) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.1) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.1) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.1) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.1) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.1) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.1) lib/action_controller/metal/params_wrapper.rb:205:in `process_action'
activerecord (3.2.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.1) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.1) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.1) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.1) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.1) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:66:in `call'
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:66:in `dispatch'
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:30:in `call'
journey (1.0.2) lib/journey/router.rb:68:in `block in call'
journey (1.0.2) lib/journey/router.rb:56:in `each'
journey (1.0.2) lib/journey/router.rb:56:in `call'
actionpack (3.2.1) lib/action_dispatch/routing/route_set.rb:589:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.1) lib/rack/etag.rb:23:in `call'
rack (1.4.1) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context'
rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/cookies.rb:338:in `call'
activerecord (3.2.1) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:443:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.1) lib/active_support/callbacks.rb:405:in `_run__304140726__call__647857879__callbacks'
activesupport (3.2.1) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.1) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.1) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.1) lib/rails/rack/logger.rb:26:in `call_app'
railties (3.2.1) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.1) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.1) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.1) lib/rack/lock.rb:15:in `call'
actionpack (3.2.1) lib/action_dispatch/middleware/static.rb:53:in `call'
railties (3.2.1) lib/rails/engine.rb:479:in `call'
railties (3.2.1) lib/rails/application.rb:220:in `call'
rack (1.4.1) lib/rack/content_length.rb:14:in `call'
railties (3.2.1) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
/home/vagrant/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/home/vagrant/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/home/vagrant/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
Request

Parameters:

{"id"=>"1"}
Show session dump

_csrf_token: "AZaUwGgrlUixvzFkXWlcntCINvgAKqoziT1AavoozDA="
session_id: "578d5c507786407d76c29ae6481e7009"
Show env dump

GATEWAY_INTERFACE: "CGI/1.1"
HTTP_ACCEPT: "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
HTTP_ACCEPT_CHARSET: "ISO-8859-1,utf-8;q=0.7,*;q=0.3"
HTTP_ACCEPT_ENCODING: "gzip,deflate,sdch"
HTTP_ACCEPT_LANGUAGE: "en-US,en;q=0.8"
HTTP_CACHE_CONTROL: "max-age=0"
REMOTE_ADDR: "10.0.2.2"
REMOTE_HOST: "10.0.2.2"
SERVER_NAME: "localhost"
SERVER_PROTOCOL: "HTTP/1.1"
Response

Headers:

None

show.html.erb

#app/views/customers/show.html.erb

<h2><div><%= @customer.name %></div></h2>

<div class="row-fluid">
  <div class="span4">
    <p>
      <h4>Address:</h4>
      <%= @customer.address %>
      <br>
      <%= @customer.county %>, <%= @customer.state %> <%= @customer.zip %><br>
      <%= link_to 'Map', street_map_url("#{@customer.address} #{@customer.county}, #{@customer.state} #{@customer.zip}"), target: "_blank" %>
    </p>
    <p>
      <h4>Phone numbers</h4>
      <% if @phones.empty? %>
        No phone number
      <% else %>
        <table class="table table-striped">
          <thead>
            <tr>
              <th>Number</th>
              <th>Type</th>
              <th></th>
            </tr>
          </thead>
          <% @phones.each do |phone| %>
            <tr>
              <td><%= phone.number %></td>
              <td><%= phone.number_type_name %></td>
              <td><%= link_to 'X', phone_path(phone), confirm: 'Are you sure?', method: :delete %></td>
            </tr>
          <% end -%>
        </table>
      <% end -%>
      <%= link_to 'Add', new_customer_phone_path(@customer), class: 'btn' %>
    </p>

    <p>
      <h4>Email addresses</h4>
      <% if @emails.empty? %>
        No email address
      <% else %>
        <table class="table table-striped">
          <thead>
            <tr>
              <th>Address</th>
              <th>Type</th>
              <th></th>
            </tr>
          </thead>
          <% @emails.each do |email| %>
            <tr>
              <td><%= email.address %></td>
              <td><%= email.address_type_name %></td>
              <td><%= link_to 'X', email_path(email), confirm: 'Are you sure?', method: :delete, class: 'btn-danger' %></td>
            </tr>
          <% end -%>
        </table>
      <% end -%>
      <%= link_to 'Add', new_customer_email_path(@customer), class: 'btn' %>
    </p>
  </div>

  <div class="span8">
    <p>
      <h4>Unpaid bills</h4><br>
      <% if @pending_bills.empty? %>
        No pending bills
      <% else %>
        <table class="table table-striped">
          <thead>
            <tr>
              <th>Amount</th>
              <th>Due date</th>
              <th></th>
              <th></th>
              <th></th>
            </tr>
          </thead>
          <% @pending_bills.each do |bill| %>
            <tr>
              <td><%= bill.amount %></td> 
              <td><%= bill.date_due %></td>
              <td><%= link_to 'Edit', edit_bill_path(bill) %></td>
              <td><%= link_to 'Mark paid', bill_path(bill,
                        bill: { paid: true }),
                        method: :put %>
              </td>
              <td><%= link_to 'Remove', bill_path(bill),
                        confirm: 'Are you sure?', 
                        method: :delete %>
              </td>
            </tr>
          <% end -%>
        </table>
      <% end -%>
      <%= link_to 'Add', new_customer_bill_path(@customer), class: 'btn' %>
    </p>

    <p>
      <h4>Paid bills</h4><br>
      <% if @paid_bills.empty? %>
        No pending bills
      <% else %>
        <table class="table table-striped">
          <thead>
            <tr>
              <th>Amount</th>
              <th>Due date</th>
              <th>Paid on</th>
              <th></th>
            </tr>
          </thead>
          <% @paid_bills.each do |bill| %>
            <tr>
             <td><%= bill.amount %></td> 
             <td><%= bill.date_due %></td>
             <td><%= bill.date_paid %></td>
             <td></td>
            </tr>
          <% end -%>
        </table>
      <% end -%>
    </p>
  </div>
</div>
<hr />

    <p>
      <h4>Notes</h4><br>
      <% if @notes.empty? %>
        No notes
      <% else %>
        <table class="table table-striped">
          <thead>
            <tr>
              <th>Title</th>
              <th>Last modified</th>
              <th></th>
            </tr>
          </thead>
          <% @notes.each do |note| %>
            <tr>
             <td><%= link_to summarise(note.content), edit_note_path(note) %></td>
             <td><%= note.updated_at %></td>
              <td><%= link_to 'X', note_path(note), confirm: 'Are you sure?', method: :delete %></td>
            </tr>
          <% end -%>
        </table>
      <% end -%>
      <br />
      <%= link_to 'Add', new_customer_note_path(@customer), class: 'btn' %>
    </p>

<hr />

  <%= link_to 'Edit customer', edit_customer_path(@customer), class: 'btn' %>
  <%= link_to 'Back', customers_path, class: 'btn' %>