lib/volt/watch.rb
def reactive_model?(model)
      Volt::Model === model ||
      # dirty way of letting anything be reactive if it wants
      (model.respond_to?(:reactive_model?) && model.reactive_model?) ||
      (model.class.respond_to?(:reactive_model?) && model.class.reactive_model?)
    end
def reactive_model?(model)
      Volt::Model === model ||
      # dirty way of letting anything be reactive if it wants
      (model.respond_to?(:reactive_model?) && model.reactive_model?) ||
      (model.class.respond_to?(:reactive_model?) && model.class.reactive_model?)
    end
Must behave like a Volt::Model
 and respond to #get(attribute)