Add some admin useful informations and SQL optimisation

photologue/models.py

@@ -15,7 +15,7 @@ from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.core.files.base import ContentFile
 from django.core.validators import RegexValidator
-from django.core.cache import caches
+from django.core.cache import cache
 from django.db import models
 from django.template.defaultfilters import slugify
 from django.urls import reverse
@@ -25,7 +25,7 @@ from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 from PIL import Image, ImageFile, ImageFilter
 
-
+caches = cache
 
 logger = logging.getLogger("photologue.models")