module Doorkeeper::AccessTokenMixin

def as_json(_options = {})
  {
    resource_owner_id: resource_owner_id,
    scope: scopes,
    expires_in: expires_in_seconds,
    application: { uid: application.try(:uid) },
    created_at: created_at.to_i,
  }.tap do |json|
    if Doorkeeper.configuration.polymorphic_resource_owner?
      json[:resource_owner_type] = resource_owner_type
    end
  end
end