Correct db migration for trashbin feature

dav_registration/models.py

@@ -72,6 +72,8 @@ class Registration(models.Model):
                                                   verbose_name=_('Einwilligung zur Datenspeicherung'))
     purge_at = models.DateTimeField(_('Zeitpunkt der Datenlöschung'))
 
+    answered_2migrate = models.BooleanField(default=False, verbose_name=_('Durch Tourleitung beantwortet'))
+
     @staticmethod
     def pk2hexstr(pk):
         return hex(pk * 113)[2:]  # 113 has no meaning, but it produce nice looking hex codes.