func (app *App) AddCName(cnames ...string) error {
	actions := []*action.Action{
		&validateNewCNames,
		&setNewCNamesToProvisioner,
		&saveCNames,
		&updateApp,
	}
	err := action.NewPipeline(actions...).Execute(app, cnames)
	rebuild.RoutesRebuildOrEnqueue(app.Name)
	return err
}
func (app *App) AddCName(cnames ...string) error {
	actions := []*action.Action{
		&validateNewCNames,
		&setNewCNamesToProvisioner,
		&saveCNames,
		&updateApp,
	}
	err := action.NewPipeline(actions...).Execute(app, cnames)
	rebuild.RoutesRebuildOrEnqueue(app.Name)
	return err
}
// AddCName adds a CName to app. It updates the attribute,
// calls the SetCName function on the provisioner and saves
// the app in the database, returning an error when it cannot save the change
// in the database or add the CName on the provisioner.