Tables' columns are nor groupable nor filterable by default

[se7entyse7en]

A column can be groupable, filterable and is_temporal.

The columns of the imported gitbase tables are nor groupable nor filterable by default. So before creating a chart that needs grouping or filtering on some columns, the user needs to get to the table configuration and mark the columns as manually.

Example of some columns of the gitbase.commits table manually marked both as groupable and filterable.

Marking them during the creation of the tables would improve the user experience.

On the other hand, each column with type TIMESTAMP is already automatically marked as is_temporal.

[smacker]

Those 2 fields affect only dashboards according to documentation:
https://superset.incubator.apache.org/tutorial.html#adding-a-new-table

For example, if the field is "filterable" you can use Filter Box on dasboard and filter data for the chart provided by a user https://superset.incubator.apache.org/faq.html#how-to-add-dynamic-filters-to-a-dashboard

It doesn't affect the creation of the charts. Though we may want to set these fields for some columns. For example, it makes sense to do for commiter_email in commits table. So user charts can be filtered on dashbord.

[smacker]

it was at least partially fixed by new gitbase

[se7entyse7en]

Let's have a look again at this once #306 is closed. Also given that this doesn't affect main functionalities. Moving this back to the backlog for now.