How to save file_field_tag ​​later in carrierwave?

Question

Ruby on Rails

Here is my form, the idea was to upload several files at once in one form, loop through and create several pictures for the gallery.
I store pictures in carrierwave, but how can I transfer the result to
it from a regular file field. The parameter returns only the file names. In theory, according to it, I should load it from the temporary storage tmp. But I don't know how to do it.
How to transfer the file value from the file_field_tag ​​field to @object.avatar. Or how can I organize another download of several files at once?

<%= bootstrap_form_for @gallery, :enctype =>"multipart/form-data" do |f| %>
        <div class="row">
          <div class="col-md-offset-4 col-md-4 col-xs-12">
            <%= f.hidden_field :tour_id %>
            <%= f.hidden_field :category_id %>
            <%= f.hidden_field :type %>
            <%= file_field_tag 'image_gallery1', :multiple => true%>
           <%= file_field_tag 'image_gallery2', :multiple => true%>
            <%= file_field_tag 'image_gallery2', :multiple => true%>


            <%= f.primary "Сохранить", class: "btn btn-primary" %>
          </div>
        </div>
    <% end %>

Answer 1

There must be an ActiveRecord model for gallery files. For example:

# Галерея
class Galery < ActiveRecord::Base
  has_many :photos
  accepts_nested_attributes_for :photos
end
#фотография
class Photo < ActiveRecord::Base
  belongs_to :galery
  # монтирование загрузчика :file -имя поля модели, где будет храниться имя файла
  mount_uploader :file, FileUploader
end
# загрузчик
class FileUploader < CarrierWave::Uploader::Base
  storage :file
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end
end

HTML

<%= form_for @galery do |galery_form| %>
  <!-- такие то поля для галереи --->
  <%= galery_form.fields_for :photos, @photos do |photo_fields| %>
    Изображение: <%= photo_fields.file_field :file %>
  <% end %>
<% end %>

@photos - collection of created models in new action