added collision dedection of new actors via registration function

architecture design proposal.md

@@ -255,6 +255,11 @@ interface ActorType {
 
 The registration of an actor type also registers every actor that is currently in the `listActorsOfThisType()`-list.
 
+To avoid new actor conflicts, a function must be called and return true when creating a new users or posts.
+
+```php
+function register_new_actor(ActorType $type, String $name) -> Bool
+```
 
 # Appendix