HasOne Through Association support

[voltechs]

It appears associations such as

has_one :owner, through: -> { system_users.where(role: 'owner') }, source: :user, class_name: 'User'

Are supported in the Rails Console, however when used in DT::Responder, seem to fail with the following error.

Cannot have a has_one :through association 'System#owner' where the :through association 'System#system_users' is a collection. Specify a has_one or belongs_to association in the :through option instead.