{
  "schema": {
    "bsonType": "object",
    "required": ["user_id", "article_id"],
    "permission": {
      ".read": true, 
      ".create": "auth.uid != null", 
      ".update": false,
      ".delete": "doc.uid == auth.uid" 
    },
    "properties": {
      "_id": {
        "description": "ID，系统自动生成"
      },
      "article_id": {
        "bsonType": "string",
        "description": "文章id，参考opendb-news-categories表"
      },
      "user_id": {
        "bsonType": "string",
        "description": "收藏者id，参考uni-id-users表"
      },
      "create_date": {
        "bsonType": "timestamp",
        "description": "收藏时间"
      }
    }
  },
  "index": [
      {
      "IndexName": "article_user_",
      "MgoKeySchema": {
        "MgoIndexKeys": [
          {
            "Name": "article_id",
            "Direction": "1"
          },
          {
            "Name": "user_id",
            "Direction": "1"
          }
        ],
        "MgoIsUnique": true
      }
    }
  ]
}