add migration guide

MIGRATION.md

@@ -9,16 +9,79 @@ This document provides instructions for migrating your codebase to accommodate b
 Drivers, Loaders, and Engines will now raises exceptions rather than returning `ErrorArtifact`s.
 Update any logic that expects `ErrorArtifact` to handle exceptions instead.
 
+#### 0.30.X
 ```python
-# Before
 artifacts = WebLoader().load("https://www.griptape.ai")
 
 if isinstance(artifacts, ErrorArtifact):
     raise Exception(artifacts.value)
+```
 
-# After
+#### 0.31.X
+```python
 try:
     artifacts = WebLoader().load("https://www.griptape.ai")
 except Exception as e:
     raise e
 ```
+
+### Changes to BaseConversationMemoryDriver
+
+`BaseConversationMemoryDriver` has updated parameter names and different method signatures for `.store` and `.load`.
+
+#### 0.30.X
+```python
+memory_driver = LocalConversationMemoryDriver()
+
+conversation_memory = ConversationMemory(
+    driver=memory_driver
+)
+
+load_result: BaseConversationMemory = memory_driver.load()
+
+memory_driver.store(conversation_memory)
+```
+
+#### 0.31.X
+```python
+memory_driver = LocalConversationMemoryDriver()
+
+conversation_memory = ConversationMemory(
+    conversation_memory_driver=memory_driver
+)
+
+load_result: tuple[list[Run], dict[str, Any]] = memory_driver.load()
+
+memory_driver.store(
+    conversation_memory.runs,
+    conversation_memory.meta
+)
+```
+
+### LocalConversationMemoryDriver `file_path` renamed to `persist_file`
+
+`LocalConversationMemoryDriver.file_path` has been renamed to `persist_file` and is now `Optional[str]`. If `persist_file` is not passed as a parameter, nothing will be persisted and no errors will be raised. `LocalConversationMemoryDriver` is now the default driver in the global `Defaults` object.
+
+#### 0.30.X
+```python
+local_driver_with_file = LocalConversationMemoryDriver(
+    file_path="my_file.json"
+)
+
+local_driver = LocalConversationMemoryDriver()
+
+assert local_driver_with_file.file_path == "my_file.json"
+assert local_driver.file_path == "griptape_memory.json"
+```
+
+#### 0.31.X
+```python
+local_driver_with_file = LocalConversationMemoryDriver(
+    persist_file="my_file.json"
+)
+
+local_driver = LocalConversationMemoryDriver()
+
+assert local_driver_with_file.persist_file == "my_file.json"
+assert local_driver.persist_file is None
+```