As a user, I want my chats to be saved

[bdleavitt]

This issue is for a: (mark with an x)

[ ] bug report -> please search issues before submitting
[x] feature request (including template changes)
[ ] documentation issue or request
[ ] regression (a behavior that used to work and stopped in a new release)

Description

Please include any relevant information, including repro steps for a bug (with log messages, version, OS, etc..)
All messages to and from the model should be recorded in the database.

Expected/desired behavior

Please include any acceptance criteria here (should look like tasks to complete for the issue to be resolved)

• System, User, and Assistant messages should be stored in the database. #30
• Messages should have a timestamp or some way to be eventually stored.
• Messages should be in stored in as near to "chat/completions" messages format as possible
• The messages and conversations should be separated/partitioned on the userid object id.

Design/Wiki Reference

Please add URLs to the design/wiki. Please note that README should be updated with relevant information as part of feature development to be code complete.

Mention any other details that might be useful