message: [postgres] adding support to serialized timedelta
diff: @@ -20,7 +20,7 @@ import sys
  import zlib
  from builtins import object
  -from datetime import date, datetime, time
  +from datetime import date, datetime, time, timedelta
  import celery
  from dateutil.parser import parse
  @@ -278,6 +278,8 @@ def base_json_conv(obj):
  return float(obj)
  elif isinstance(obj, uuid.UUID):
  return str(obj)
  + elif isinstance(obj, timedelta):
  + return str(obj)
  def json_iso_dttm_ser(obj):
  