[Avatar] Fix, sodass korrekte url rausgegeben wird.

flaschengeist/models/user.py

@@ -1,7 +1,7 @@
 from datetime import date
 from typing import Optional
 
-from flask import url_for
+from flask import url_for, request
 from sqlalchemy.orm.collections import attribute_mapped_collection
 
 from . import ModelSerializeMixin
@@ -68,7 +68,7 @@ class User(db.Model, ModelSerializeMixin):
 
     @property
     def avatar_url(self):
-        return url_for("users.get_avatar", userid=self.userid)
+        return f'{request.url_root}/{url_for("users.get_avatar", userid=self.userid)}'
 
     @property
     def roles(self):