Getting error when run node bot.js

[nimitbhargava]

I followed the steps

git clone https://github.com/slugbay/slack-welcome-bot
cd slack-welcome-bot
npm install
node bot.js

When run node bot.js getting [ERROR]: No Slack token provided.

My app.json content

➜  slack-welcome-bot git:(master) ✗ cat app.json
{
    "name": "Slack Welcome Bot",
    "description": "This Slack application connects to your slack team and greets new joiners with a sweet custom message",
    "keywords": [
        "productivity",
        "slack",
        "greetings",
        "bot",
        "resources",
        "developers",
        "slugbay",
        "sluggy"
    ],
    "website": "https://www.slugbay.com",
    "repository": "https://github.com/slugbay/slack-welcome-bot",
    "logo": "https://github.com/slugbay/slack-welcome-bot/raw/master/logo.png",
    "env": {
        "SLACK_TOKEN": {
            "description": "Slack Bot Token",
            "value": "my-key-from-slack",
            "required": "true"
        },
        "SLACK_MESSAGE": {
            "description": "Your Welcome message (JSON)",
            "value": "{\"text\": \"Hey {fist_name} {last_name} akka *{username}*,\n\nI'm a welcome bot. Welcome to our Slack team! :tada:\nLet me give you some instructions.\"}",
            "required": "true"
        }
    }
}

Also node and npm version

➜  slack-welcome-bot git:(master) ✗ node --version
v10.13.0
➜  slack-welcome-bot git:(master) ✗ npm --version
6.11.3