def subscribe
      @subscription.subscribe(with_email_subscription: params[:with_email_subscription].to_s.to_boolean(true),
                              with_optional_targets:   params[:with_optional_targets].to_s.to_boolean(true))
      return_back_or_ajax
    end
def subscribe
      @subscription.subscribe(with_email_subscription: params[:with_email_subscription].to_s.to_boolean(true),
                              with_optional_targets:   params[:with_optional_targets].to_s.to_boolean(true))
      return_back_or_ajax
    end
Subscribes to the notification.

 POST /:target_type/:target_id/subscriptions/:id/subscribe
 @overload open(params)
   @param [Hash] params Request parameters
   @option params [String] :with_email_subscription ('true')  If the subscriber also subscribes notification email
   @option params [String] :with_optional_targets   ('true')  If the subscriber also subscribes optional targets
   @option params [String] :filter                  (nil)     Filter option to load subscription index (Nothing as all, 'configured' or 'unconfigured')
   @option params [String] :limit                   (nil)     Limit to query for subscriptions
   @option params [String] :reverse                 ('false') If subscription index and unconfigured notification keys will be ordered as earliest first
   @option params [String] :filtered_by_key         (nil)     Key of the subscription for filter
   @return [Responce] JavaScript view for ajax request or redirects to back as default