added command: run rake django-admin[sync_user_info] to sync info to discussion

common/djangoapps/student/management/commands/sync_user_info.py

+##
+## One-off script to sync all user information to the discussion service (later info will be synced automatically)
+
+
+from django.core.management.base import BaseCommand
+from django.contrib.auth.models import User
+import comment_client
+
+
+class Command(BaseCommand):
+    help = \
+'''
+Sync all user ids, usernames, and emails to the discussion
+service'''
+
+    def handle(self, *args, **options):
+        for user in User.objects.all().iterator():
+            comment_client.update_user(user.id, {
+                'id': user.id,
+                'username': user.username,
+                'email': user.email
+            })