This was a good point a few years ago. But since then there's been at least 3 good projects that allow you to easily add admin panel to rails app:

Rails Admin: https://github.com/sferik/rails_admin Active Admin: https://github.com/activeadmin/activeadmin Administrate: https://github.com/thoughtbot/administrate

I know there is many gems but I have still yet to see them used in the wild. My colleagues seems to avoid using them for some reasons and discouraged me to even try them. Maybe the strength of Django is having the admin by default so most Django app (gems) comes with a admin and those admins aggregate together in a coherent admin application.

This is true. The Django admin works out of the box. Getting the activeadmin gem to work for Rails 4? Not so much:

https://stackoverflow.com/questions/16426398/active-admin-in...

Rails has this available via a gem: Active Admin (http://activeadmin.info/).

It would take about as much time as it would take to add Active Admin or Rails Admin to the gemfile.