Update docs about garrison

Author: trey-stafford

doc/releasing.md

@@ -9,5 +9,24 @@ To release a new version:
 - Tag latest commit on `main` with the version, and push. This will trigger a
   build of the `data-access-tool-api` and `data-access-tool-server` images with
   the given version tag.
-- Deploy the latest change with the
-  [data-access-tool-vm](https://github.com/nsidc/data-access-tool-vm).
+- Deploy the latest change with
+  [garrison](https://bitbucket.org/nsidc/garrison). See the
+  [section on garrison](#garrison) below for more info.
+
+## garrison
+
+[garrison](https://bitbucket.org/nsidc/garrison) is a deployment system for
+NSIDC applications deployed to a VM on NSIDC infrastructure.
+
+The [jenkins-cd](http://ci.jenkins-cd.apps.int.nsidc.org:8080) Jenkins VM
+provides a mechanism for doing garrison deployments of the
+`data-access-tool-backend` to integration and QA.
+
+The
+[Deploy Project with Garrison](https://ci.jenkins-ops-2022.apps.int.nsidc.org/job/Deploy_Project_with_Garrison/)
+job defined in the Ops Jenkins is used by Ops to deploy to staging and
+production.
+
+See the [data-access-tool-vm](https://github.com/nsidc/data-access-tool-vm)
+project for additional details and VM configuration for the
+`data-access-tool-backend`.