INTPYTHON-438 Add CONTRIBUTING.md and README (#39)

README.md

@@ -6,4 +6,50 @@ It includes integrations between MongoDB, Atlas, LangChain, and LangGraph.
 It contains the following packages.
 
 - `langchain-mongodb` ([PyPI](https://pypi.org/project/langchain-mongodb/))
-- `langgraph-checkpoint-mongodb`
+- `langgraph-checkpoint-mongodb` ([PyPI](https://pypi.org/project/langgraph-checkpoint-mongodb/))
+
+## Features
+
+- Vector store
+    -[MongoDBAtlasVectorSearch](https://python.langchain.com/docs/integrations/vectorstores/mongodb_atlas/)
+- Message histories
+    - [MongoDBChatMessageHistory](https://python.langchain.com/docs/integrations/memory/mongodb_chat_message_history/)
+- Model caches
+    - [MongoDBCache](https://python.langchain.com/docs/integrations/providers/mongodb_atlas/#mongodbcache)
+    - [MongoDBAtlasSemanticCache](https://python.langchain.com/docs/integrations/providers/mongodb_atlas/#mongodbatlassemanticcache)
+- Retrievers
+    - [MongoDBAtlasHybridSearchRetriever](https://python.langchain.com/docs/integrations/providers/mongodb_atlas/#hybrid-search-retriever)
+    - [MongoDBAtlasFullTextSearchRetriever](https://python.langchain.com/docs/integrations/providers/mongodb_atlas/#full-text-search-retriever)
+    - `MongoDBAtlasParentDocumentRetriever` - new feature, docs coming soon!
+- LangGraph persistence
+    - `MongoDBSaver` - new feature, docs coming soon!
+
+**Note**: This repository replaces all MongoDB integrations currently present in the `langchain-community` package. Users are encouraged to migrate to this repository as soon as possible.
+
+## Installation
+
+You can install the `langchain-mongodb` package from PyPI.
+
+```bash
+pip install langchain-mongodb
+```
+
+You can install the `langgraph-checkpoint-mongodb` package from PyPI as well:
+
+```bash
+pip install langgraph-checkpoint-mongodb
+```
+
+## Usage
+
+See [langchain-mongodb usage](libs/mongodb/README.md#usage) and [langgraph-checkpoint-mongodb usage](libs/langgraph-checkpoint-mongodb/README.md#usage).
+
+For more detailed usage examples and documentation, please refer to the [LangChain documentation](https://python.langchain.com/docs/integrations/providers/mongodb_atlas/).
+
+## Contributing
+
+See the [Contributing Guide](CONTRIBUTING.md).
+
+## License
+
+This project is licensed under the [MIT License](LICENSE).