dokku: Dokku scripts doesn't work with dockerfile deployment

Hi,

I’m trying to run a simple command during the predeploy phase with an app.json at the root of my repository but nothing happen, I always get the following :

I have put an app.json at the root of my repo, an other one inside an app/ folder, and a scripts.dokku at the root, but no one work.

{
  "name": "jubiwee-api",
  "description": "Jubiwee core API",
  "scripts": {
    "dokku": {
      "predeploy": "touch /app/predeploy.test",
    }
  },
  "env": {
    "APP_ENV": "production",
    "APP_DEBUG": "false",
    "CACHE_DRIVER": "memcached",
    "QUEUE_DRIVER": "sync"
  }
}

• uname -a: Linux scw-d78731 4.5.1-std-1 #1 SMP Mon Apr 18 19:58:58 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
• free -m:
• docker version:
• docker -D info:
• sigil -v: 0.4.0
• docker run -ti gliderlabs/herokuish:latest herokuish version:
• dokku version: 0.6.4
• dokku plugin:

Dokku was installed through the standard way described in the doc.

Thanks