Added method to get the PersonTarget of a Booking.

app/Booking.php

@@ -54,6 +54,21 @@ class Booking extends Model
         return null;
     }
 
+    /**
+     * Get the person target of the booking. If the booking consists of more than
+     * one sub-booking, null is returned.
+     *
+     * @return App\AccountType
+     */
+    public function personTarget()
+    {
+        if ($this->isSimple()) {
+            return $this->subBookings->first()->personTarget;
+        }
+
+        return null;
+    }
+    
     /**************************************************************************
      * INDIRECT PROPERTIES                                                    *
      **************************************************************************/