createDocument method
Creates a document in the specified collection
Implementation
@override
Future<String> createDocument(String collection, Map<String, dynamic> data) async {
final documents = _documents;
final collectionId = _sanitizeCollection(collection);
final id = _extractId(data) ?? _generateId();
final document = firestore.Document(
fields: _encodeFields(data),
);
await documents.createDocument(
document,
_documentsParent,
collectionId,
documentId: id,
);
return id;
}