ruby on rails 3 - Not able to get url from uploaded image, undefined method `url' error on has_many associated model -

undefined method `url' #<galleryphoto:0x007f80c05a4ba8>  10:   <%= @gallery.date %> 11: </p> 12:  13: <%= @gallery.gallery_photos.first.url %> 14:  15:  16: <%= link_to 'edit', edit_gallery_path(@gallery) %> 

i attempting create photo album system in rails app albums created , images uploaded via paperclip. unable .url method work on show page display image. way set this:

gallery model (has many gallery_photos)

galleryphotos model(belongs_to gallery)

gallery show:

<p id="notice"><%= notice %></p>  <p>   <b>gallery name:</b>   <%= @gallery.gallery_name %> </p>  <p>   <b>date:</b>   <%= @gallery.date %> </p>  <%= @gallery.gallery_photos.first.url %>   <%= link_to 'edit', edit_gallery_path(@gallery) %> | <%= link_to 'back', galleries_path %> 

gallery model

class gallery < activerecord::base     attr_accessible :date, :gallery_name, :gallery_photos_attributes     has_many :gallery_photos, :dependent => :destroy      accepts_nested_attributes_for :gallery_photos  end 

gallery_photo model

class galleryphoto < activerecord::base     attr_accessible :photo, :caption, :date, :gallery_id      belongs_to :gallery      has_attached_file :photo,:styles => { :large => "300x300<", :medium => "300x300>", :thumb => "100x100>" }, :default_url => "/images/:style/missing.png"  end 

gallery controller

  def new     @gallery = gallery.new     @gallery.gallery_photos.build # added   end    def show     @gallery = gallery.find(params[:id])   end    def create     @gallery = gallery.new(params[:gallery])      respond_to |format|       if @gallery.save!         format.html { redirect_to @gallery, notice: 'gallery created.' }         format.json { render json: @gallery, status: :created, location: @gallery }       else         format.html { render action: "new" }         format.json { render json: @gallery.errors, status: :unprocessable_entity }       end     end   end 

the table mysql, , running through vagrant virtual system. inserting on new, , making it. on new inserting data table galleries , gallery_photos. no matter do, cannot url out of it.

from https://github.com/thoughtbot/paperclip, url method belongs to
has_attached_file :photo, correct way retrieve url is

@gallery.gallery_photos.first.photo.url