How to upload image to server because of controller without model in ruby on rails

Question

I need to upload image to server folder through url( for example: wwww.example.com.folder/image
My photo_controller.rb

class PhotoController < ApplicationController
  def index
    require 'net/http'
    require 'json'
  end
end

My index.html.erb

  <div>
    <%= form_tag( method: "post", :multipart => true) do %>
      <%= file_field_tag 'picture' %>
      <p></p>
      <%= submit_tag("Send",class: "btn btn-primary") %>
    <% end %>
  </div>

When I click Send, photo must be in folder(photo attached)enter image description here.May be I need to use json or other.

And of course without model Does anyone have any ideas?