fixes #13978 - replace AR value_to_boolean with our caster
In Rails 4.2, value_to_boolean was moved further into ActiveRecord's column type classes. Replace the use of this internal method with Foreman's own well-tested caster.
Related issues
Refactor #13978: Replace AR connection value_to_boolean method with Foreman::Cast
fixes #13978 - replace AR value_to_boolean with our caster
In Rails 4.2, value_to_boolean was moved further into ActiveRecord's
column type classes. Replace the use of this internal method with
Foreman's own well-tested caster.