Document Stein review priorities

This captures the user-facing themes we aim to deliver this cycle,
which we'll use as a reference throughout the cycle, in addition to
focusing our review with the runways process.

Change-Id: I18cf0367de4b11f8b515d0d1c9800f6fabf54be6

priorities/stein-priorities.rst

@@ -4,4 +4,34 @@
 Stein Project Priorities
 ========================
 
-TODO: fill this in after the PTG
+Last cycle, we used only `review runways`_ to capture priorities at any given
+time throughout the cycle. We discussed it at the Project Team Gathering (PTG)
+during the `Rocky retrospective`_ and determined that while runways were
+overall a good process for focusing our review efforts, they were not
+sufficient in conveying any overall priorities or themes we were trying to
+accomplish over the cycle as a team.
+
+So, this cycle, we came up with a set of `user-facing themes`_ at the PTG, for
+ourselves to refer to throughout the cycle and help us to organize our work and
+review outside of runways. Themes are not meant to preempt anything in review
+runways.
+
+The user-facing themes for this cycle are:
+
+* Compute nodes capable to upgrade and exist with nested resource
+  providers for multiple GPU types
+
+* Multi-cell operational enhancements: resilience to "down" or
+  poor-performing cells and cross-cell instance resize
+
+* Volume-backed user experience and API hardening: ability to specify
+  volume type during boot-from-volume, detach/attach of root volume, and
+  volume-backed rebuild
+
+These are the user-visible features and functionality we aim to deliver
+and we will keep tabs on these efforts throughout the cycle to keep them
+making progress.
+
+ .. _review runways: https://etherpad.openstack.org/p/nova-runways-stein
+ .. _Rocky retrospective: https://etherpad.openstack.org/p/nova-rocky-retrospective
+ .. _user-facing themes: https://etherpad.openstack.org/p/nova-ptg-stein-priorities