1. Ruby on Rails

Ruby on Rails framework has now its own layer called `ruby-on-rails`,
be sure to add this layer to your dotfile if you use it.

2. Django

Django framework has now its own layer called `django`,
be sure to add this layer to your dotfile if you use it.

3. Salt

Salt layer requires the YAML layer, be sure to add the `yaml` layer
to your dotfile if you use `salt` layer.