Rails 4, updating nested polymorphic resource - ruby-on-rails

Question

I have set up polymorphic resource using accepts_nested_attributes_for but for some reason whenever I try to update, instead of just updating the current record, it just create a new one instead. Can anyone tell me what the problem is? Thanks.
vendors_controller.rb
class VendorsController < ApplicationController
before_action :authenticate_user! #check if user logged in
before_action :set_vendor, only: [:show, :edit, :update, :destroy]
def index
#vendors = current_company.vendors
end
def new
#vendor = current_company.vendors.build
#vendor.addresses.build
end
def create
#vendor = current_company.vendors.build(vendor_params)
if #vendor.save
flash[:notice] = 'New Vendor Added'
redirect_to vendors_url
else
flash[:error] = 'Could not save vendor information. Please try again.'
render 'new'
end
end
def show
end
def edit
##vendor = Vendor.find(params[:id])
##vendor.addresses.find_or_initialize_by(addressable_id: #vendor.id, addressable_type: 'Vendor')
end
def update
##vendor = Vendor.find(params[:id])
if #vendor.update(vendor_params)
flash[:notice] = 'Vendor Updated'
redirect_to vendors_path
else
flash[:error] = 'Could not save vendor information. Please try again.'
render 'edit'
end
end
def destroy
#Vendor.find(params[:id]).destroy
#vendor.destroy
flash[:notice] = "Asset deleted"
redirect_to vendors_url
end
private
def vendor_params
params.require(:vendor).permit(:name, :vendorID, :contact, :email, :phone, :image, :remove_image, addresses_attributes: [:street_1, :street_2, :city, :state, :zip] )
end
def set_vendor
#vendor = Vendor.find(params[:id])
end
def current_company
current_user.company
end
end
_form.html.erb
<div class="row">
<div class="col-md-4 col-md-offset-4">
<div class="card card-block" style="background-color:#f5f5f5">
<%= form_for #vendor do |f| %>
<div class="form-group">
<%= f.label :name, 'Vendor Name' %><br />
<%= f.text_field :name, autofocus: true, required: true, class:'form-control' %>
</div>
<div class="form-group">
<%= f.label :vendorID, 'Vendor ID/Number' %><br />
<%= f.text_field :vendorID, class:'form-control' %>
</div>
<div class="form-group">
<%= f.label :contact, 'Main Contact Person' %><br />
<%= f.text_field :contact, class:'form-control' %>
</div>
<div class="form-group">
<%= f.label :email %><br />
<%= f.email_field :email, class:'form-control' %>
</div>
<div class="form-group">
<%= f.label :phone %><br />
<%= f.phone_field :phone, class:'form-control' %>
</div>
<%= f.fields_for :addresses do |a| %>
<div class="form-group">
<%= a.label :street_1, 'Street' %><br />
<%= a.text_field :street_1, class:'form-control' %>
</div>
<div class="form-group">
<%= a.label :street_2, 'Street 2 (Optional)' %><br />
<%= a.text_field :street_2, class:'form-control' %>
</div>
<div class="form-group">
<%= a.label :city, 'City' %><br />
<%= a.text_field :city, class:'form-control' %>
</div>
<div class="form-group">
<%= a.label :state, 'State' %><br />
<%= a.text_field :state, class:'form-control' %>
</div>
<div class="form-group">
<%= a.label :zip, 'Zip Code' %><br />
<%= a.text_field :zip, class:'form-control' %>
</div>
<% end %>
<div class="actions form-group"><br>
<%= f.submit 'Save Vendor', class: 'btn btn-primary' %>
<%= link_to 'Cancel', :back, class: 'btn btn-default' %>
</div>
<% end %>
</div>
vendor.rb
class Vendor < ActiveRecord::Base
belongs_to :company
has_many :asset
has_many :addresses, as: :addressable, dependent: :destroy
accepts_nested_attributes_for :addresses, reject_if: RejectDeeplyNested.blank?
end
address.rb
class Address < ActiveRecord::Base
belongs_to :addressable, polymorphic: true
end

Answer 1

you need to change your permitted parameters like this
params.require(:vendor).permit(:name, :vendorID, :contact, :email, :phone, :image, :remove_image, addresses_attributes: [:street_1, :street_2, :city, :state, :zip, :id] )

Answer 2

You need to add optional: true to your relationship:
class Address < ApplicationRecord
belongs_to :addressable, polymorphic: true, optional: true
end
Forgot to mention, that optional is available only on Rails > 5