class NestedFieldTest include Mongoid::Document field :title, type: String belongs_to :field_test, inverse_of: :nested_field_tests belongs_to :another_field_test, inverse_of: :nested_field_tests include Mongoid::Timestamps has_one :comment, as: :commentable, autosave: true accepts_nested_attributes_for :comment, allow_destroy: true, reject_if: proc { |attributes| attributes['content'].blank? } end