authors save post

book.rb

class Book < ActiveRecord::Base

	has_attached_file :jacket_cover, :styles => { :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/:style/missing.png"
	validates_attachment_content_type :jacket_cover, :content_type => /\Aimage\/.*\Z/

	validates :jacket_cover, :title, :slug, :synopsis, :body, :age, :publisher, presence: true
	validates_uniqueness_of :title

	extend FriendlyId
	friendly_id :title, use: [:slugged, :finders]

	belongs_to :author
	belongs_to :gallery
	has_many :stories
	has_many :images

	accepts_nested_attributes_for :author
	accepts_nested_attributes_for :gallery
	accepts_nested_attributes_for :images

	scope :available, ->{ where(available: true) }
	scope :unavailable, ->{ where(available: [nil, false]) }

end

books_controller.rb

 # GET /books/new
  def new
    @book = Book.new
    @book.build_author
    @gallery = @book.build_gallery 
    @gallery.images.build
  end

  # GET /books/1/edit
  def edit
  end

  # POST /books
  # POST /books.json
  def create
    #raise params.inspect
    @book = Book.create(book_params)

    #binding.pry

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

form.html.erb

//book form 

<%= simple_form_for(@book, :html => { :multipart => true }) do |f| %>
  <%= f.error_notification %>

  <div class="inputs">
  	<%= f.file_field :jacket_cover %>
    <%= f.input :title %>
    <%= f.input :synopsis, :as => :ckeditor, :label => false, :input_html => {  :ckeditor => { :toolbar => 'Full', :height => 400 } } %>
    <%= f.input :body, :as => :ckeditor, :label => false, :input_html => {  :ckeditor => { :toolbar => 'Full', :height => 400 } } %>
    <%= f.input :age %>
    <%= f.input :publisher %>
  </div>
  <%= f.simple_fields_for :author do |a| %>
	   <%= a.input :name %>
  	 <%= a.input :biography, :as => :ckeditor, :label => false, :input_html => {  :ckeditor => { :toolbar => 'Full', :height => 400 } } %>
  <% end %>

    <%= f.simple_fields_for :gallery do |builder| %>
      <%= render 'galleries/form', :f => builder %>
    <% end %>


  <%= f.select( :author_id, Author.all.map {|u| [u.name,u.id]}, {:include_blank => false}) %>
  <%#= f.select :author_id, Author.all.collect {|a| [ a.name, a.id ] } %>

  <div class="actions">
    <%= f.button :submit %>
  </div>
<% end %>