Great! Looking at the request/response cycle, we need four parts to build the travel app: models, controllers, routes, and views.
Let’s begin by creating the models.
Generate a model named Tag.
Generate another model named Destination.
In app/models/tag.rb add a has_many method, like this:
class Tag < ActiveRecord::Base
has_many :destinations
end In app/models/destination.rb, add a belongs_to method:
belongs_to :tag