Fixed: ugettext has been deprecated

Fixed: Multiple Upload for Eventpics

src/mahjong_ranking/models.py

@@ -12,7 +12,7 @@ from django.core.exceptions import ValidationError
 from django.db import models
 from django.urls import reverse
 from django.utils import timezone
-from django.utils.translation import ugettext as _
+from django.utils.translation import gettext as _
 
 from events.models import Event
 from . import DAN_RANKS_DICT, LOGGER, set_dirty