persist zulip

modules/nixos/zulip.nix

@@ -41,4 +41,14 @@
       EXTERNAL_HOST = config.services.zulip.host;
     };
   };
+  # persist
+  environment.persistence."/persist".directories = [
+    # messages
+    "/var/lib/rabbitmq"
+    # uploads
+    "/var/lib/zulip"
+
+    # contrived, but in the store a couple layers down
+    # "/var/lib/redis-zulip"
+  ];
 }