This is a brilliant idea.

README.md

app/controllers/tags_controller.rb

app/models/application_record.rb

app/models/tag.rb

app/models/tag_set.rb

app/models/tag_with_path.rb

app/views/tags/_list.html.erb

app/views/tags/_tag.html.erb

app/views/tags/category.html.erb

app/views/tags/children.html.erb

config/initializers/activerecord_relation.rb

db/scripts/create_tags_path_view.rb

db/scripts/create_tags_path_view.sql