app.json

{
  "env": {
    "MY_SECRET_TOKEN": {
      "description": "A secret key for verifying the integrity of signed cookies.",
      "value": "secret"
    },
    "WEB_CONCURRENCY": {
      "description": "The number of processes to run.",
      "value": "5"
    }
  },
  "formation": {
    "web": {
      "quantity": 2,
      "size": "Private-S"
    },
    "worker": {
      "quantity": 2,
      "size": "Private-S"
    }    
  },
  "addons": [
    {
      "plan": "heroku-redis:premium-1"
    }
  ],
  "stack": "container",
  "environments": {
    "review": {
      "addons": ["heroku-redis:premium-0"],
      "MY_SECRET_TOKEN": {
        "description": "A secret key for verifying the integrity of signed cookies.",
        "value": "another_secret"
      },
      "WEB_CONCURRENCY": {
        "description": "The number of processes to run.",
        "value": "12"
      }
    }
  }
}