customer model

class Customer < ActiveRecord::Base
  belongs_to :order

    validates :name, presence: true,
            allow_blank: false,
            uniqueness: true
end

new.html.erb

<h1>Place a new Ice Cream order</h1>

<p>
</p>


<%= link_to 'Orders', controller: 'orders' %>
<%= link_to 'Flavors', controller: 'flavors' %>
<%= link_to 'Toppings', controller: 'toppings' %>
<%= link_to 'Containments', controller: 'containments' %>




<%= form_for @order do |f| %>
  // order fields
  <%= f.fields_for :customer do |customer| %>
    // customer fields
  <% end %>
<% end %>


<%= form_for @order do |f| %>
Your info:
<ul>
  <%= f.fields_for :customer do |customer| %>
  <li>
    <%= customer.label :name %>
    <%= customer.text_field :name %>

    <%= customer.label :address %>
    <%= customer.text_field :address %>

    <%= customer.label :phone %>
    <%= customer.text_field :phone %>

    <%= customer.label :email %>
    <%= customer.text_field :email %>
  </li>
  <% end %>
  </ul>
<%= f.submit %>
<% end %>

  Flavors:
<ul>

</ul>
<!--   <%= f.fields_for :flavor do |flavor_form| %>

  <li>
    <%= flavor_form.label :name, "Pick your flavor" %>
    <%= flavor_form.collection_select :order_id, Flavor.all,:id,:name %>
    <%= flavor_form.select :flavor, Flavor.all.map { |c| [c.name, c.id] }%>
  </li>
  <% end %> -->

order model

class Order < ActiveRecord::Base
  has_one :containment
  has_one :flavor, :through => :containment

  has_many :toppings
  has_many :toppings, :through => :containment

  has_one :customer
  accepts_nested_attributes_for :customer, :containment, :flavor, :toppings

  validates :name, presence: true,
            allow_blank: false,
            uniqueness: true


end

orders_controller

require 'pry'
class OrdersController < ApplicationController
  require 'mandrill'
  # order = Order::OrdersController.new

  def index
    @orders = Order.all
  end

  def new
    @order = Order.new
    @order.build_customer
    # @order.build_containment
    # @order.build_flavor
    # @order.toppings.build
  end


  def show
    @order = Order.find(params[:id])
  end


  def create
    @order = Order.new(order_params)
    @customer = Customer.new

    if @order.save
      # Emailer.order_email(order)
      redirect_to order_path@order
    else
      render 'new'
    end
  end

  private
  def order_params
    params.require(:order).permit(
      :customer_id,
      # :containtment_id,
      # :flavor_id,
      # :topping_id,
      customers_attributes: [ :id, :name, :address, :phone, :email]#,
      # containments_attributes: [:id, :name]
      # flavors_attributes: [:id, :name],
      # toppings_attributes: [:id, :name],
      )
  end

end

schema

# encoding: UTF-8
# This file is auto-generated from the current state of the database. Instead
# of editing this file, please use the migrations feature of Active Record to
# incrementally modify your database, and then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your
# database schema. If you need to create the application database on another
# system, you should be using db:schema:load, not running all the migrations
# from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended that you check this file into your version control system.

ActiveRecord::Schema.define(version: 20150602055146) do

  create_table "containments", force: :cascade do |t|
    t.string  "name"
    t.string  "image_url"
    t.integer "order_id"
  end

  create_table "customers", force: :cascade do |t|
    t.string  "name"
    t.text    "address"
    t.integer "phone"
    t.string  "email"
    t.integer "order_id"
  end

  create_table "flavors", force: :cascade do |t|
    t.string   "name"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.string   "image_url"
  end

  create_table "orders", force: :cascade do |t|
    t.integer "customer_id"
    t.integer "containment_id"
    t.integer "flavor_id"
    t.integer "topping_id"
  end

  create_table "toppings", force: :cascade do |t|
    t.string "name"
    t.string "image_url"
  end

end