Update Aether production pod configs

Change-Id: Ifec91b19b7a7512885b5e63b9129499b8f539f59
diff --git a/deployment-configs/aether/apps/staging/cassandra-gcp.yaml b/deployment-configs/aether/apps/staging/cassandra-gcp.yaml
new file mode 100644
index 0000000..00fbdde
--- /dev/null
+++ b/deployment-configs/aether/apps/staging/cassandra-gcp.yaml
@@ -0,0 +1,9 @@
+fullnameOverride: "cassandra"
+image:
+  tag: "2.1.20"
+persistence:
+  enabled: true
+  storageClass: "zonal-ssd"
+config:
+  cluster_domain: "staging.central"
+  endpoint_snitch: "GossipingPropertyFileSnitch"