usage in readme

README.md

@@ -7,3 +7,41 @@
 
 WordPress Library to ask for good rate in repository.
 ===================================================
+
+### Usage
+
+When using in shipping zones:
+```php
+private function init_repository_rating() {
+    $time_tracker = new ShippingMethodWatcher(
+        FedexShippingService::UNIQUE_ID,
+        'plugin_activation_flexible-shipping-fedex/flexible-shipping-fedex.php',
+        '28-11-2019',
+        FedexShippingMethod::class
+    );
+    $this->add_hookable( $time_tracker );
+    $this->add_hookable(
+        new RatingPetitionNotice(
+            $time_tracker,
+            FedexShippingService::UNIQUE_ID,
+            $this->plugin_info->get_plugin_name()
+        )
+    );
+}
+```
+
+When using in shipping method:
+
+```php
+private function init_repository_rating() {
+    $time_tracker = new ShippingMethodGlobalSettingsWatcher( FedexShippingService::UNIQUE_ID );
+    $this->add_hookable( $time_tracker );
+    $this->add_hookable(
+        new RatingPetitionNotice(
+            $time_tracker,
+            FedexShippingService::UNIQUE_ID,
+            $this->plugin_info->get_plugin_name()
+        )
+    );
+}
+```