Rails + Reform + Bootstrap + Ajax Modal Form

_modal.html.haml

# simple_form Reform Form for creating a basic postal address
# errors will be shown on the violating fields
= simple_form_for(@form, remote: true) do |f|
  .modal-dialog
    .modal-content
      .modal-header
        %button.close{"aria-hidden" => "true", "data-dismiss" => "modal", :type => "button"} ×
        %h3.modal-title
          New Address for
          = @customer.name
      .modal-body
        = f.hidden_field :customer_id
        = f.input :type, collection: [['Shipping','ShippingAddress'], ['Billing', 'BillingAddress']], include_blank: false, input_html: { class: 'form-control'}
        = f.input :line_1, label: 'Line 1', input_html: { class: 'form-control' }
        = f.input :line_2, label: 'Line 2', input_html: { class: 'form-control' }
        = f.input :line_3, label: 'Line 3', input_html: { class: 'form-control' }
        = f.input :line_4, label: 'Line 4', input_html: { class: 'form-control' }
        = f.input :line_5, label: 'Line 5', input_html: { class: 'form-control' }
        = f.input :line_6, label: 'Line 6', input_html: { class: 'form-control' }
        = f.input :country, collection: Address.countries, include_blank: false, input_html: { class: 'form-control' }

      .modal-footer
        = f.button :submit, class: 'btn btn-lg btn-success'
        %button.btn.btn-lg.btn-danger{"aria-hidden" => "true", "data-dismiss" => "modal"} Close

address.rb

# Address Model
# nice and clean now that the form handles all the validations
class Address < ActiveRecord::Base
  belongs_to :customer

  # Countries list for addresses. (there are gems for this...)
  def self.countries
    ['Ireland']
  end

end

address_form.rb

# Reform form object.
# - no more messing with strong params.
# - the form handles all the validations.
class AddressForm < Reform::Form
  include Reform::Form::ActiveModel::FormBuilderMethods # This is removed in later Reform 2.2
  include Reform::Form::ActiveModel::ModelReflections # this is removed in 2.2

  property :customer_id,   type: Types::Form::Int
  property :type,          default: 'ShippingAddress'
  property :primary,       type: Types::Form::Bool, default: false
  property :delivery_foc,  type: Types::Form::Bool, default: false
  property :line_1
  property :line_2
  property :line_3
  property :line_4
  property :line_5
  property :line_6
  property :country,        default: 'Ireland'

  validates :type,
            :line_1,
            :line_2,
            :country,
            :customer_id,
            presence: true
end

addresses_controller.rb

class AddressesController < ApplicationController

  def new
    @customer = Customer.find params[:customer_id]
    @address = @customer.shipping_addresses.build
    @form = AddressForm.new(@address)

    respond_to do |format|
      format.js # renders new.js.erb which will insert the modal form into the page
    end
  end

  def create
    @customer = Customer.find params[:address][:customer_id]
    @form = AddressForm.new(Address.new)
    respond_to do |format|
      if @form.validate(params[:address]) && @form.save
        format.js # renders the create.js.erb which will remove the modal
      else
        format.js   { render :new }
      end
    end
  end
end

create.js.erb

// Used to hide the modal if there is no errors.
// and update the address dropdown with the newly created one.
<% if @form.errors.blank? %>
  // Hide the modal
  $('#modal-window').modal('hide');

  // add the newly created address to the list of options
  $('#sales_order_shipping_address_id').append("<option value='>" + "<%= @form.id %>" + "'>" + "<%= @form.line_1 %>" + "</option>");

<% else %>
  // dont hide let it show the errors in the UI
<% end %>

new.js.erb

// renders the form inside the div 
$("#modal-window").html("<%= escape_javascript(render 'addresses/modal') %>");

new_order.html.haml

-# Some page where the modal appears over.

-# The target for the JS to put the modal content
#modal-window.modal.fade{ 'role' => "dialog" }

-# Link to trigger modal
=link_to 'New Address', new_customer_address_path(current_user.active_reseller_id), remote: true, data: { toggle: 'modal', target: '#modal-window'}