This shouldn't be in the root of the docs: it's not easily discoverable
and it doesn't belong there. We also modify the header style to better
match the OpenStack style guide [1] and set things up for a future guide
on writing database migrations.
[1] https://docs.openstack.org/doc-contrib-guide/rst-conv/titles.html#cg-titles
Change-Id: I277b9ad8d275aa21d2c3ce478d2a30e4f6e5f0ba
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>