Integration of base url

[lightningRalf]

Hello Paul,
is it possible to add OPEN_AI_BASE or openai.api_base endpoint

default:
openai.api_base = "https://api.openai.com/v1/chat/completions"

https://platform.openai.com/docs/models/default-usage-policies-by-endpoint

In this way I am possible to try to use local modals with it / with this method for example.
https://github.com/lm-sys/FastChat/blob/main/docs/openai_api.md

Model I want to try to use: https://huggingface.co/bigcode/starcoderplus
And also Orca once it is released.

Thanks in advance.
Greetings from Germany

[paul-gauthier]

Sure thing. Just merged PR #18 with this change.

Note that the base url should just be https://api.openai.com/v1 without the /chat/completions.