Point to rolling restarts

lib/kamal/cli/templates/deploy.yml

@@ -78,3 +78,8 @@ registry:
 # hitting 404 on in-flight requests. Combines all files from new and old
 # version inside the asset_path.
 # asset_path: /rails/public/assets
+
+# Configure rolling deploys by setting a wait time between batches of restarts.
+# boot:
+#   limit: 10 # Can also specify as a percentage of total hosts, such as "25%"
+#   wait: 2