Enhancing the configuration of the time range in the user guide to explore data using Superset

[SellamiRami]

Is your feature request related to a problem? Please describe.

By following the user guide to explore data using Superset, I can't display the chart. After investigation, I find the solution which consists in customizing the time range from 2019-06-23 16:00:00 to 2019-06-28 16:00:00 (instead of choosing the default option last quarter).

Describe the solution you'd like
To fix this limitation, the documentation should be enhanced as follow (go to the part of creating a new chart in the user guide):

• In the Data tab
  • in Time section,
    • Time Grain: hour.
    • in Time range, press the custom tab
      • Start / end: copy/paste 2019-06-23 16:00:00 and 2019-06-28 16:00:00