Support for slerp merging models (#455)

* support for slerp merging models

* docs

* update docs

* format'

llms/mlx_lm/SERVER.md

@@ -0,0 +1,63 @@
+# HTTP Model Server
+
+You use `mlx-lm` to make an HTTP API for generating text with any supported
+model. The HTTP API is intended to be similar to the [OpenAI chat
+API](https://platform.openai.com/docs/api-reference).
+
+Start the server with: 
+
+```shell
+python -m mlx_lm.server --model <path_to_model_or_hf_repo>
+```
+
+For example:
+
+```shell
+python -m mlx_lm.server --model mistralai/Mistral-7B-Instruct-v0.1
+```
+
+This will start a text generation server on port `8080` of the `localhost`
+using Mistral 7B instruct. The model will be downloaded from the provided
+Hugging Face repo if it is not already in the local cache.
+
+To see a full list of options run:
+
+```shell
+python -m mlx_lm.server --help
+```
+
+You can make a request to the model by running:
+
+```shell
+curl localhost:8080/v1/chat/completions \
+  -H "Content-Type: application/json" \
+  -d '{
+     "messages": [{"role": "user", "content": "Say this is a test!"}],
+     "temperature": 0.7
+   }'
+```
+
+### Request Fields
+
+- `messages`: An array of message objects representing the conversation
+  history. Each message object should have a role (e.g. user, assistant) and
+  content (the message text).
+
+- `role_mapping`: (Optional) A dictionary to customize the role prefixes in
+  the generated prompt. If not provided, the default mappings are used.
+
+- `stop`: (Optional) An array of strings or a single string. Thesse are
+  sequences of tokens on which the generation should stop.
+
+- `max_tokens`: (Optional) An integer specifying the maximum number of tokens
+  to generate. Defaults to `100`.
+
+- `stream`: (Optional) A boolean indicating if the response should be
+  streamed. If true, responses are sent as they are generated. Defaults to
+  false.
+
+- `temperature`: (Optional) A float specifying the sampling temperature.
+  Defaults to `1.0`.
+
+- `top_p`: (Optional) A float specifying the nucleus sampling parameter.
+  Defaults to `1.0`.