`goldrush` is needed in escript.

```
--- a/rebar.config
+++ b/rebar.config
@@ -33,7 +33,7 @@
 {erl_opts, [{src_dirs, [src]},
            {parse_transform, lager_transform}]}.

-{escript_incl_apps, [lager, getopt, bear, folsom, ibrowse, riakc, mochiweb, protobuffs, velvet]}.
+{escript_incl_apps, [lager, getopt, bear, folsom, ibrowse, riakc, mochiweb, protobuffs, velvet, goldrush]}.
```