FireStore v1

private void addNewContact(){
        Map<String, Object>newContact = new HashMap<>();
        newContact.put(NAME_KEY, "John");
        newContact.put(EMAIL_KEY, "john@gmail.com");
        newContact.put(PHONE_KEY, "080-0808-009");
        db.collection("PhoneBook").document("Contacts").set(newContact)
                .addOnSuccessListener(new OnSuccessListener<Void>() {
                    @Override
                    public void onSuccess(Void aVoid) {
                        Toast.makeText(MainActivity.this, "User Registered",
                                Toast.LENGTH_SHORT).show();
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Toast.makeText(MainActivity.this, "ERROR" +e.toString(),
                                Toast.LENGTH_SHORT).show();
                        Log.d("TAG", e.toString());
                    }
                });