Create an upload controller action for Rails app - ruby-on-rails

Question

I'm making a Rails app, and want to add an upload feature with allows users to upload multiple entries at once through an Excel spreadsheet as opposed to entering one entry at a time.
Ideally, I was hoping to add a separate Upload/Submit portion to the bottom of the new.html.erb file (the bold portion being the Upload HTML.erb):
...
<div class="actions">
<%= f.submit %>
</div>
<% end %>
**<div class="field">
Or Upload Multiple Entries <br />
<%= form_tag({:action => :upload}, :multipart => true) do %>
<%= file_field_tag 'multi_doc' %>
<% end %>
</div>**
Here is my routes.rb file:
Dataway::Application.routes.draw do
devise_for :users
resources :revenue_models do
get 'upload', :on => :collection
end
root :to => "home#index"
end
And my revenue_models_controller (haven't developed the action at all yet, now just a redirect):
...
def upload
redirect_to revenue_models_path
end
I have followed the rails guides for Uploading files as well as for Routing files and I keep getting an error when I attempt to open the /new view I have modified:
Routing Error
No route matches {:action=>"upload", :controller=>"revenue_models"}
Try running rake routes
When I run rake route, I get an entry for the upload action:
upload_revenue_models GET /revenue_models/upload(.:format) revenue_models#upload
In the end, what I would like to do is upload an excel file with multiple entries, parse it, and conditionally add each data row to my database, which I was under the impression I could specify in the upload action. Please help!

Answer 1

Please use form_for instead form_tag.
Second What is multi_doc is a field/attribute of revenue_model?. I guess is a field/attribute of revenue_model.
Third, Where is your instance variable revenue_model in the form?
Fourth, You have to create first a instance variable of your Model, on your action/controller where you are showing the form, for example #revenue_model = RevenueModel.new.
After try this code:
<%= form_for(#revenue_model, :method => :get, :html => {:multipart => true}, :url => { :controller => "revenue_models", :action => "upload"})) do |f| %>
<%= f.file_field :multi_doc %>
<%= f.submit :id => "any_id" %>
<% end %>
The question is very confusing, trying to clarify your question specifying the name of your actions and the names of the files in your views.
Regards!