feat: unique email for users

later42/models/urls.py

@@ -1,6 +1,8 @@
 from django.contrib.auth.models import User
 from django.db import models
 
+User._meta.get_field('email')._unique = True
+
 
 class URL(models.Model):
     id = models.AutoField(auto_created=True, primary_key=True)