#for fresh property (with review)
 def new
    @property = Property.new
    @property.property_reviews.build
 end

class Property < ActiveRecord::Base
  has_many :property_reviews, :dependent => :destroy
  accepts_nested_attributes_for :property_reviews
end

<%= render :partial => 'form' %>

<%= form_for @property, :html => {multipart: true} do |f| %>
    <%= render 'shared/error_messages', object: f.object %>

    <%= f.label :address, "Complete Address" %>
    <%= f.text_area :address, rows: 3 %>

    <%= f.fields_for :property_reviews do |review| %>
      <%= render "review_fields", r: review %>
    <% end %>

<%= f.submit "Submit", class: "btn btn-large btn-primary" %>

<p>
   <%= r.label :comments %>
   <%= r.text_area :comments, rows: 5 %>
   ..
   ..
</p>

# add another review to existing property
  def add_new_review
    @property = Property.find(params[:id])
    @review = @property.property_reviews.build
  end

<b><%= @property.address %></b>
<%= form_for @review do |r| %>
  <%= render "review_fields" %>

  <%= f.submit "Submit", class: "btn btn-large btn-primary" %>
<% end %>

undefined method `property_reviews_path' for #<#<Class:0xa2ac3a8>:0xa5e487c>

<%= form_for @review do |r| %>

resources :property_reviews

<%= form_for [@property, @review] do |r| %>