update for valid non-subdomains

contracts/models.py

@@ -20,7 +20,7 @@ from users.models import User
 class SubdomainValidatedURLField(models.URLField):
     validators = [
         URLValidator(schemes=("https",)),
-        RegexValidator(regex=r"https:\/\/.*\.pirati.cz(\/|$).*"),
+        RegexValidator(regex=r"https:\/\/(.*\.|)pirati.cz(\/|$).*"),
     ]