refactor, better class namespace intergration

app/Models/Shop/CustomerAddress.php

@@ -10,11 +10,11 @@ class CustomerAddress extends Model
 
     public function Customer()
     {
-        return $this->belongsTo('App\Models\Shop\Customer');
+        return $this->belongsTo(Customer::class);
     }
 
     public function Orders()
     {
-        return $this->hasMany('App\Models\Shop\Order');
+        return $this->hasMany(Order::class);
     }
 }