{
  "bsonType": "object",
  "required": ["user_id", "article_id", "months", "create_time"], // 必填字段
  "permission": {
    "read": true,
		"create": "doc._id == auth.uid || 'admin' in auth.role",
		"update": "doc._id == auth.uid ||  'admin' in auth.role",
		"delete": "doc._id == auth.uid || 'admin' in auth.role"
  },
  "properties": {
    "_id": {
      "description": "ID，系统自动生成"
    },
    "months": {
      "bsonType": "int",
      "title": "累计月数",
	  "defaultValue": 0, 
      "minimum": 0
    },
    "user_id": {
      "bsonType": "string",
      "title": "用户ID",
      "foreignKey": "uni-id-users._id", 
      "trim": "both",
      "errorMessage": "用户ID不能为空"
    },
    "article_id": {
      "bsonType": "string",
      "title": "文章ID",
      "trim": "both",
      "errorMessage": "文章ID不能为空"
    },
    "gift_value": {
      "bsonType": "int",
      "title": "礼物价值",
      "minimum": 0,
      "defaultValue": 0, 
      "errorMessage": "礼物价值不能小于1"
    },
    "create_time": {
      "bsonType": "timestamp",
      "title": "创建时间",
      "defaultValue": {
        "$env": "now" // 自动填充服务器时间[1](@ref)
      }
    }
  }
}