정의된 애들만 들어간다
Mongoose Schema urlMongoose Schema typeMongoose Schema preMongoose Schema postMongoose Schema methodMongoose Schema virtualMongoose Schema statics methodMongoose Schema versionmongoose schema optionsmongoose "_id" field can't be deleted
On Mongoose, the "id" property is created by default and it's a virtual one returning the value of "_id". You don't need to do that yourself.
https://stackoverflow.com/questions/29407567/mongoose-id-field-cant-be-deleted
