Rails 生成 Token 方法
Devise
Devise.friendly_token(24).upcase
SecureRandom
SecureRandom.hex(24)
generate_unique_secure_token
self.class.generate_unique_secure_token
has_secure_token
class App < ActiveRecord::Base
has_secure_token :name
end
app = App.new
app.save
app.name # => "BunurUTaTEZbnr1S64Csec9h"
app.regenerate_name # => true