add empty django_env for ci

Author: artcz

intbot/intbot/settings.py

@@ -306,5 +306,8 @@ def warn_if_missing(name, default=""):
     # Currently used only for collecting staticfiles in docker
     DEBUG = False
 
+elif DJANGO_ENV == "ci":
+    DEBUG = False
+
 else:
     raise ValueError(f"Unsupported DJANGO_ENV `{DJANGO_ENV}`")