[
    {
        "IndexName": "article_user_",
        "MgoKeySchema": {
            "MgoIndexKeys": [
                {
                    "Name": "article_id",
                    "Direction": "1"
                },
                {
                    "Name": "user_id",
                    "Direction": "1"
                }
            ],
            "MgoIsUnique": true
        }
    }
]