Add public join policy setting

zooid/config.go

@@ -27,6 +27,7 @@ type Config struct {
 	} `toml:"info"`
 
 	Policy struct {
+		PublicJoin      bool `toml:"public_join"`
 		StripSignatures bool `toml:"strip_signatures"`
 	} `toml:"policy"`
 

zooid/management.go

@@ -289,6 +289,10 @@ func (m *ManagementStore) ValidateJoinRequest(event nostr.Event) (reject bool, e
 		return true, "invalid: you have been banned from this relay"
 	}
 
+	if m.Config.Policy.PublicJoin {
+		return false, ""
+	}
+
 	claimTag := event.Tags.Find("claim")
 
 	if claimTag == nil {