Add chrony to keep time synchronised

roles/chrony.nix

@@ -0,0 +1,11 @@
+# NixOps configuration for the hosts running a Chrony service
+
+{ config, ... }:
+
+{
+
+  services.chrony = {
+    enable = true;                                # Enable Chrony
+  };
+
+}

roles/host_common.nix

@@ -5,6 +5,7 @@
 {
 
   imports = [
+    ./chrony.nix
     ./tmux.nix
   ];