Virtus: Coercing boolean attributes

TLDR

Do it like this:

attribute :active, Virtus::Attribute::Boolean

Long story

In Virtus Show archive.org snapshot you define attribute with their type like this:

attribute :name, String
attribute :birthday, Date

When defining a boolean attributes, you will probably write it like this:

attribute :active, Boolean

The problem is, there is not actually a Boolean class in Ruby (there's only TrueClass and FalseClass), so use Virtus::Attribute::Boolean instead.

The reason while Boolean sometimes survives compilation is that many libraries define a global Boolean class for some reason. That class however won't work with virtus.