Elixir- phoenix server side rendering react using std_json_io and react-stdio - reactjs

Question

I followed the tutorial from https://medium.com/#chvanikoff/phoenix-react-love-story-reph-1-c68512cfe18 and developed an application but with different versions.
elixir - 1.3.4
phoenix - 1.2.1
poison - 2.0
distillery - 0.10
std_json_io - 0.1
The application ran successfully when running locally.
Bur when created a mix release(MIX_ENV=prod mix release --env=prod --verbose) and ran rel/utopia/bin/utopia console(the otp application name was :utopia), I ran into error
Interactive Elixir (1.3.4) - press Ctrl+C to exit (type h() ENTER for help)
14:18:21.857 request_id=idqhtoim2nb3lfeguq22627a92jqoal6 [info] GET /
panic: write |1: broken pipe
goroutine 3 [running]:
runtime.panic(0x4a49e0, 0xc21001f480)
/usr/local/Cellar/go/1.2.2/libexec/src/pkg/runtime/panic.c:266 +0xb6
log.(*Logger).Panicf(0xc210020190, 0x4de060, 0x3, 0x7f0924c84e38, 0x1, ...)
/usr/local/Cellar/go/1.2.2/libexec/src/pkg/log/log.go:200 +0xbd
main.fatal_if(0x4c2680, 0xc210039ab0)
/Users/alco/extra/goworkspace/src/goon/util.go:38 +0x17e
main.inLoop2(0x7f0924e0c388, 0xc2100396f0, 0xc2100213c0, 0x7f0924e0c310, 0xc210000000, ...)
/Users/alco/extra/goworkspace/src/goon/io.go:100 +0x5ce
created by main.wrapStdin2
/Users/alco/extra/goworkspace/src/goon/io.go:25 +0x15a
goroutine 1 [chan receive]:
main.proto_2_0(0x7ffce6670101, 0x4e3e20, 0x3, 0x4de5a0, 0x1, ...)
/Users/alco/extra/goworkspace/src/goon/proto_2_0.go:58 +0x3a3
main.main()
/Users/alco/extra/goworkspace/src/goon/main.go:51 +0x3b6
14:18:21.858 request_id=idqhtoim2nb3lfeguq22627a92jqoal6 [info] Sent 500 in 1ms
14:18:21.859 [error] #PID<0.1493.0> running Utopia.Endpoint terminated
Server: 127.0.0.1:8080 (http)
Request: GET /
** (exit) an exception was raised:
** (Protocol.UndefinedError) protocol String.Chars not implemented for {#PID<0.1467.0>, :result, %Porcelain.Result{err: nil, out: {:send, #PID<0.1466.0>}, status: 2}}
(elixir) lib/string/chars.ex:3: String.Chars.impl_for!/1
(elixir) lib/string/chars.ex:17: String.Chars.to_string/1
(utopia) lib/utopia/react_io.ex:2: Utopia.ReactIO.json_call!/2
(utopia) web/controllers/page_controller.ex:12: Utopia.PageController.index/2
(utopia) web/controllers/page_controller.ex:1: Utopia.PageController.action/2
(utopia) web/controllers/page_controller.ex:1: Utopia.PageController.phoenix_controller_pipeline/2
(utopia) lib/utopia/endpoint.ex:1: Utopia.Endpoint.instrument/4
(utopia) lib/phoenix/router.ex:261: Utopia.Router.dispatch/2
goon got panicked and hence the porcelain. Someone please provide a solution.
Related issues: https://github.com/alco/porcelain/issues/13
EDIT: My page_controller.ex
defmodule Utopia.PageController do
use Utopia.Web, :controller
def index(conn, _params) do
visitors = Utopia.Tracking.Visitors.state
initial_state = %{"visitors" => visitors}
props = %{
"location" => conn.request_path,
"initial_state" => initial_state
}
result = Utopia.ReactIO.json_call!(%{
component: "./priv/static/server/js/utopia.js",
props: props
})
render(conn, "index.html", html: result["html"], props: initial_state)
end
end