1. Map을 이용한 insert 방식 private fun saveUserDB(firebaseUser: FirebaseUser) { val userId = firebaseUser.uid.orEmpty() val userEmail = firebaseUser.email.orEmpty() val updateUserDB = userDB.child(userId) val user = mutableMapOf() user["userId"] = userId user["userEmail"] = userEmail auth.currentUser?.providerData?.forEach { userInfo -> user["userSnsType"] = userInfo.providerId } updateUserDB.updateC..
