Add *oser-cs.fr to CORS whitelist

oser_backend/oser_backend/settings/common.py

@@ -126,7 +126,9 @@ CORS_ORIGIN_REGEX_WHITELIST = (
     # - https://oser-frontend-dev.herokuapp.com
     # (but also https://unknown.herokuapp.com...)
     # Essentially allows any frontend hosted on Heroku to send CORS requests.
-    r'^(https?://)?(.+\.)?herokuapp\.com$'
+    r'^(https?://)?(.+\.)?herokuapp\.com$',
+    # Allow any app hosted on *oser-cs.fr
+    r'^(https?://)?(.+\.)?oser-cs\.fr$',
 )
 X_FRAME_OPTIONS = 'DENY'  # refuse to serve in an <iframe>