Documentation: Update README. Add Changelog.

CHANGES.md

@@ -0,0 +1,6 @@
+# LangChain CrateDB Adapter Changelog
+
+
+## Unreleased
+
+- Make it work

README.md

@@ -1,45 +1,115 @@
 # langchain-cratedb
 
-This package contains the LangChain integration with CrateDB
+[![Release Notes](https://img.shields.io/github/release/crate/langchain-cratedb)](https://github.com/crate/langchain-cratedb/releases)
+[![CI](https://github.com/crate/langchain-cratedb/actions/workflows/ci.yml/badge.svg)](https://github.com/crate/langchain-cratedb/actions/workflows/ci.yml)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
+[![Bluesky](https://img.shields.io/badge/Bluesky-0285FF?logo=bluesky&logoColor=fff&label=Follow%20%40CrateDB)](https://bsky.app/search?q=cratedb)
+
+» [Documentation]
+| [Changelog]
+| [Community Forum]
+| [PyPI]
+| [Issues]
+| [Source code]
+| [License]
+| [CrateDB]
+
+The `langchain-cratedb` package implements core LangChain abstractions
+using [CrateDB] or [CrateDB Cloud].
+
+The package is released under the MIT license. 
+
+Feel free to use the abstraction as provided or else modify them / extend them
+as appropriate for your own application.
+
+## Requirements
+
+The package currently only supports the Python DB API driver, available per
+[crate] package.
 
 ## Installation
 
 ```bash
 pip install -U langchain-cratedb
 ```
 
-And you should configure credentials by setting the following environment variables:
+## Usage
 
-* TODO: fill this out
+### ChatMessageHistory
 
-## Chat Models
+The chat message history abstraction helps to persist chat message history
+in a CrateDB table.
 
-`ChatCrateDB` class exposes chat models from CrateDB.
+CrateDBChatMessageHistory is parameterized using a `table_name` and a `session_id`.
 
-```python
-from langchain_cratedb import ChatCrateDB
+The `table_name` is the name of the table in the database where 
+the chat messages will be stored.
+
+The `session_id` is a unique identifier for the chat session. It can be assigned
+by the caller using `uuid.uuid4()`.
 
-llm = ChatCrateDB()
-llm.invoke("Sing a ballad of LangChain.")
+```python
+import uuid
+
+from langchain_core.messages import SystemMessage, AIMessage, HumanMessage
+from langchain_cratedb import CrateDBChatMessageHistory
+
+# Create the table schema (only needs to be done once)
+dburi = "crate://crate@localhost:4200"
+table_name = "chat_history"
+session_id = str(uuid.uuid4())
+
+# Initialize the chat history manager
+chat_history = CrateDBChatMessageHistory(
+    table_name,
+    session_id,
+    connection=dburi,
+)
+
+# Add messages to the chat history
+chat_history.add_messages([
+    SystemMessage(content="Meow"),
+    AIMessage(content="woof"),
+    HumanMessage(content="bark"),
+])
+
+print(chat_history.messages)
 ```
 
-## Embeddings
 
-`CrateDBEmbeddings` class exposes embeddings from CrateDB.
+### VectorStore
 
-```python
-from langchain_cratedb import CrateDBEmbeddings
+See example notebook at [CrateDBVectorStore].
 
-embeddings = CrateDBEmbeddings()
-embeddings.embed_query("What is the meaning of life?")
-```
 
-## LLMs
-`CrateDBLLM` class exposes LLMs from CrateDB.
+## Project Information
 
-```python
-from langchain_cratedb import CrateDBLLM
+### Acknowledgements
+Kudos to the authors of all the many software components this library is
+inheriting from and building upon, most notably the [langchain-postgres]
+package, and [langchain] itself.
 
-llm = CrateDBLLM()
-llm.invoke("The meaning of life is")
-```
+### Contributing
+The `langchain-cratedb` package is an open source project, and is
+[managed on GitHub]. The project is still in its infancy, and
+we appreciate contributions of any kind.
+
+### License
+The project uses the MIT license, like the langchain-postgres project
+it is deriving from.
+
+
+[Changelog]: https://github.com/crate/langchain-cratedb/blob/main/CHANGES.md
+[Community Forum]: https://community.cratedb.com/
+[crate]: https://pypi.org/project/crate/
+[CrateDB]: https://cratedb.com/database
+[CrateDB Cloud]: https://cratedb.com/database/cloud
+[CrateDBVectorStore]: https://github.com/crate/langchain-cratedb/blob/main/docs/vectorstores.ipynb
+[Documentation]: https://cratedb.com/docs/guide/integrate/langchain/
+[Issues]: https://github.com/crate/langchain-cratedb/issues
+[langchain]: https://github.com/langchain-ai/langchain
+[langchain-postgres]: https://github.com/langchain-ai/langchain-postgres
+[License]: https://github.com/crate/langchain-cratedb/blob/main/LICENSE
+[managed on GitHub]: https://github.com/crate/langchain-cratedb
+[PyPI]: https://pypi.org/project/langchain-cratedb/
+[Source code]: https://github.com/crate/langchain-cratedb