Keep GET params in return URL

When signing in from a page containing GET params, like
`/budgets/1/investments?heading_id=4`, we were redirected to a URL
without those GET params; in this case, `/budgets/1/investments`.

Using the request fullpath, as recommended in the devise documentation,
keeps these parameters when redirecting.

app/controllers/application_controller.rb

@@ -108,7 +108,7 @@ class ApplicationController < ActionController::Base
 
     def set_return_url
       if !devise_controller? && controller_name != "welcome" && is_navigational_format?
-        store_location_for(:user, request.path)
+        store_location_for(:user, request.fullpath)
       end
     end