Remove unused serialization functions

src/action/setusertimezone.ts

@@ -1,6 +1,6 @@
 /*
  * server component for the TimeLimit App
- * Copyright (C) 2019 Jonas Lochmann
+ * Copyright (C) 2019 - 2020 Jonas Lochmann
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
@@ -34,12 +34,6 @@ export class SetUserTimezoneAction extends ParentAction {
     this.timezone = timezone
   }
 
-  serialize = (): SerializedSetUserTimezoneAction => ({
-    type: 'SET_USER_TIMEZONE',
-    userId: this.userId,
-    timezone: this.timezone
-  })
-
   static parse = ({ userId, timezone }: SerializedSetUserTimezoneAction) => (
     new SetUserTimezoneAction({ userId, timezone })
   )