Only show file templates which are available for the selected file type

config/routes.rb

@@ -1,7 +1,11 @@
 FILENAME_REGEXP = /[\w\.]+/ unless Kernel.const_defined?(:FILENAME_REGEXP)
 
 Rails.application.routes.draw do
-  resources :file_templates
+  resources :file_templates do
+    collection do
+      get 'by_file_type/:file_type_id', as: :by_file_type, to: :by_file_type
+    end
+  end
   resources :code_harbor_links
   resources :request_for_comments
     get '/my_request_for_comments', as: 'my_request_for_comments', to: 'request_for_comments#get_my_comment_requests'