message: [docs faq] how do I add new columns to an existing table
diff: @@ -124,3 +124,16 @@ __ https://www.sqlite.org/lockingv3.html
  One work around is to create a symlink from ~/.superset to a directory located on a non-NFS partition.
  Another work around is to change where superset stores the sqlite database by adding ``SQLALCHEMY_DATABASE_URI = 'sqlite:////new/localtion/superset.db'`` in superset_config.py (create the file if needed), then adding the directory where superset_config.py lives to PYTHONPATH environment variable (e.g. ``export PYTHONPATH=/opt/logs/sandbox/airbnb/``).
  +
  +How do I add new columns to an existing table
  +---------------------------------------------
  +
  +Table schemas evolve, and Superset needs to reflect that. It's pretty common
  +in the life cycle of a dashboard to want to add a new dimension or metric.
  +To get Superset to discover your new columns, all you have to do is to
  +go to ``Menu -> Sources -> Tables``, click the ``edit`` icon next to the
  +table who's schema has changed, and hit ``Save`` from the ``Detail`` tab.
  +Behind the scene, the new columns will get merged it. Following this,
  +you may want to
  +re-edit the table afterwards to configure the ``Column`` tab, check the
  +appropriate boxes and save again.
  