Ruby on Rails provides a model generator you can use to create ActiveRecord models. Simply use rails generate model and provide the model name.

$ rails g model user

In addition to the model file in app/models, the generator will also create:

• the Test in test/models/user_test.rb
• the Fixtures in test/fixtures/users.yml
• the database Migration in db/migrate/XXX_create_users.rb

You can also generate some fields for the model when generating it.

$ rails g model user email:string sign_in_count:integer birthday:date

This will create the columns email, sign_in_count and birthday in your database, with the appropriate types.