Fix adding a user to a group in admin section

app/controllers/admin/groups_controller.rb

@@ -42,7 +42,7 @@ class Admin::GroupsController < Admin::ApplicationController
   end
 
   def members_update
-    @group.add_users(params[:user_ids].split(','), params[:access_level], current_user)
+    @group.add_users(params[:user_ids].split(','), params[:access_level], current_user: current_user)
 
     redirect_to [:admin, @group], notice: 'Users were successfully added.'
   end