ajax swap and sort methods

  def change_main_image
    project = Project.find(params[:id])
    image = Image.find(params[:image_id])
    render :partial => 'main_image', :locals => {:project => project, :image => image}
  end

  def sort_images
    @project = Project.find(params[:id])
    @project.images.each do |image|
      # we must add one to compensate for the zero based index.
      image.position = params["project_#{@project.id}_thumbnails"].index(image.id.to_s) + 1
      image.save
    end
    render :nothing => true
  end