Create a model (lets call it User) by running:
$ rails g model User
which will generate the file app/models/user.rb:
class User
include Mongoid::Document
end
This is all you need to have a model (albeit nothing but an id field). Unlike ActiveRecord, there is no migration files. All the database information for the model is contained in the model file.
Timestamps are not automatically included in your model when you generate it. To add created_at and updated_at to your model, add
include Mongoid::Timestamps
to your model underneath include Mongoid::Document like so:
class User
include Mongoid::Document
include Mongoid::Timestamps
end