AttributeError when sending prompts

[elwais]

With the latest commit (1731445), attempting to query any valid model returns the following Python error:

AttributeError: type object 'Model' has no attribute 'from_name'

The file app/server/chat.py attempts to do Model.from_name(), but the Gemini-API library installed has since deprecated Model and removed its from_name method, making the server unusable.

I've put out a PR at #158 that modifies app/server/chat.py. Please have a look and see if it resolves the issue.

[Goojoe]

The same problem occurred, but it works fine after using your branch. Thank you.