Add ENABLE_DISCUSSION_EMAIL_DIGEST feature, to enable discussion emails digest by default for all users

common/djangoapps/student/views.py

@@ -86,6 +86,7 @@ from bulk_email.models import Optout, CourseAuthorization
 import shoppingcart
 from openedx.core.djangoapps.user_api.models import UserPreference
 from lang_pref import LANGUAGE_KEY
+from notification_prefs.views import enable_notifications
 
 import track.views
 
@@ -1589,6 +1590,12 @@ def create_account(request, post_override=None):  # pylint: disable-msg=too-many
 
     (user, profile, registration) = ret
 
+    if settings.FEATURES.get('ENABLE_DISCUSSION_EMAIL_DIGEST'):
+        try:
+            enable_notifications(user)
+        except Exception:
+            log.exception("Enable discussion notifications failed for user {id}.".format(id=user.id))
+
     dog_stats_api.increment("common.student.account_created")
 
     email = post_vars['email']