fix js errors

app/controllers/template_documents_controller.rb

@@ -4,7 +4,9 @@ class TemplateDocumentsController < ApplicationController
   load_and_authorize_resource :template
 
   def create
-    return head :unprocessable_entity if params[:blobs].blank? && params[:files].blank?
+    if params[:blobs].blank? && params[:files].blank?
+      return render json: { error: 'File is missing' }, status: :unprocessable_entity
+    end
 
     old_fields_hash = @template.fields.hash