Set default value for Active Record attribute

Suppose you want to set a default attribute value for a model so that all new instances of the model have a default attribute. Something like this:

User.new.bio
=> 'Mysterious creature'

You can do this with the attribute method:

class User < ApplicationRecord
  attribute :bio, :string, default: 'Mysterious creature'
end

You can also use a lambda if you want to dynamically generate the value:

class User < ApplicationRecord
  attribute :bio, :string, default: -> { Faker::Job.title }
end