add registrations to customer gui

common/models/EventRegistration.php

@@ -68,11 +68,19 @@ class EventRegistration extends \yii\db\ActiveRecord
 
 
     public function getEvent(){
-        return $this->hasOne(Event::class,['id' => 'id_event']);
+        return $this->hasOne($this->getEventClass(),['id' => 'id_event']);
     }
 
     public function getCustomer(){
-        return $this->hasOne(Customer::class,['id' => 'id_customer']);
+        return $this->hasOne($this->getCustomerClass(),['id' => 'id_customer']);
     }
 
+
+    public function getEventClass(){
+        return Event::class;
+    }
+
+    public function getCustomerClass(){
+        return Customer::class;
+    }
 }