Some newcomers sometimes browse gitea or GitHub to learn about
OpenStack and naturally open the openstack/openstack repository,
only to find a confusing and pretty technical explanation about
submodule tracking and the subtleties of tested combinations of
components.
Provide some general information about OpenStack first, to
redirect those lose souls to friendler shores.
Change-Id: I41cde655f6c5d08fc482c40953687570acd59d3f
zuul gates all of the contained projects in an effective single
timeline. This means that OpenStack, across all of the projects, does
already have a sequence of combinations that have been explcitily
tested, but it's non-trivial to go from a single commit of a particular
project to the commits that were tested with it.
Gerrit's submodule tracking feature will update a super project every
time a subproject is updated, so the specific sequence created by zuul
will be captured by the super project commits.
Thierry Carrez