fix: fix class names in README.md (#31)

Author: craig08

README.md

@@ -36,7 +36,7 @@ source <your-env>/bin/activate
 ## Usage
 
 ```python
-from langchain_google_memorystore_redis import MemorystoreVectorstore, MemorystoreLoader, MemorystoreChatMessageHistory
+from langchain_google_memorystore_redis import RedisVectorStore, MemorystoreDocumentLoader, MemorystoreChatMessageHistory
 ```
 
 ## Contributing
@@ -61,4 +61,4 @@ This is not an officially supported Google product.
 [billing]: https://cloud.google.com/billing/docs/how-to/modify-project#enable_billing_for_a_project
 [api]: https://console.cloud.google.com/flows/enableapi?apiid=memorystore.googleapis.com
 [auth]: https://googleapis.dev/python/google-api-core/latest/auth.html
-[venv]: https://virtualenv.pypa.io/en/latest/
+[venv]: https://virtualenv.pypa.io/en/latest/