template.json

{ 
    "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
    },
    "variables": {},
    "resources": [
        {
            "type": "Microsoft.Network/networkSecurityGroups",
            "name": "app2-nsg-uiq76ih4woyp4",
            "apiVersion": "2018-02-01",
            "location": "westus2",
            "properties": {
                "securityRules": [
                    {
                        "name": "testing-rule-2",
                        "properties": {
                            "description": "just a test.",
                            "protocol": "Tcp",
                            "sourcePortRange": "*",
                            "destinationPortRange": "8000",
                            "sourceAddressPrefix": "*",
                            "destinationAddressPrefix": "*",
                            "access": "Allow",
                            "priority": 4000,
                            "direction": "Inbound",
                            "sourcePortRanges": [],
                            "destinationPortRanges": [],
                            "sourceAddressPrefixes": [],
                            "destinationAddressPrefixes": []
                        }
                    }
                ]
            },
            "dependsOn": []
        }
    ]
}