add a bit more commentary

ci-tools/deploy-to-staging

 #!/usr/bin/env nix-shell
 #!nix-shell -i bash -p jp
 
+#
+# Tell all servers belonging to a certain grid that they should update
+# themselves to the latest configuration associated with that grid.
+#
+
 set -euxo pipefail
 
+# Get the path to the ssh key which authorizes us to deliver this
+# notification.
 DEPLOY_KEY=$1
 shift
 
+# Get the name of the grid to which we're going to deliver notification.  This
+# corresponds to the name of one of the directories in the top-level `morph`
+# directory.
 GRIDNAME=$1
 shift
 
-# Tell one node to update itself.
+# Tell one server to update itself.
 update_one_node() {
     deploy_key=$1
     shift
@@ -20,6 +30,7 @@ update_one_node() {
     ssh -i "${deploy_key}" "deployment@${node}"
 }
 
+# Tell all servers belonging to one grid to update themselves.
 update_grid_nodes() {
     deploy_key=$1
     shift
@@ -32,9 +43,10 @@ update_grid_nodes() {
     # to filter out later.
     nodes=$(nix eval --json '(builtins.attrNames (import ./morph/${gridname}/grid.nix))')
 
-    # Tell every system in the network to update itself.
+    # Tell every server in the network to update itself.
     for node in ${nodes}; do
 	if [ "${node}" = "network" ]; then
+	    # This isn't a server, it's part of the morph configuration.
 	    continue
 	fi
 	update_one_node "${deploy_key}" "${node}"