message: [bugfix] preserve order in groupby
  Recently in
  I introduced an issue where the order of groupby fields might change.
  This addresses this issue and will preserve ordering.
diff: @@ -112,10 +112,13 @@ class BaseViz(object):
  def query_obj(self):
  """Building a query object"""
  form_data = self.form_data
  - groupby = form_data.get("groupby") or []
  + gb = form_data.get("groupby") or []
  metrics = form_data.get("metrics") or []
  columns = form_data.get("columns") or []
  - groupby = list(set(groupby + columns))
  + groupby = []
  + for o in gb + columns:
  + if o not in groupby:
  + groupby.append(o)
  is_timeseries = self.is_timeseries
  if DTTM_ALIAS in groupby:
  