devel/rubygem-cocoon: New port

Cocoon makes it easier to handle nested forms.

Nested forms are forms that handle nested models and attributes in one
form; e.g. a project with its tasks or an invoice with its line items.

Cocoon is form builder-agnostic, so it works with standard Rails,
Formtastic, or SimpleForm. It is compatible with rails 3, 4 and 5.

This project is not related to Apache Cocoon.

Sponsored by: Nepustil