Fixed sync without specifying tags filter

boards/management/commands/sync_with_server.py

@@ -59,8 +59,14 b' class Command(BaseCommand):'
         else:
             logger.info('Running LIST request...')
             h = httplib2.Http()
+
+            tags = []
+            tags_str = options.get('tags')
+            if tags_str:
+                tags = tags_str.split(',')
+
             xml = SyncManager.generate_request_list(
-                opening_post=options.get('thread'), tags=options.get('tags').split(',')).encode()
+                opening_post=options.get('thread'), tags=tags).encode()
             response, content = h.request(list_url, method="POST", body=xml)
             if response.status != 200:
                 raise Exception('Server returned error {}'.format(response.status))