Lit-GPT integration docs (#1089)

* lit-gpt integration

* mention PT lightning

docs/source/integrations.mdx

@@ -29,6 +29,25 @@ Bitsandbytes is also easily usable from within Accelerate.
 
 Please review the [bitsandbytes section in the Accelerate docs](https://huggingface.co/docs/accelerate/en/usage_guides/quantization).
 
+
+
+# PyTorch Lightning and Lightning Fabric
+
+Bitsandbytes is available from within both
+- [PyTorch Lightning](https://lightning.ai/docs/pytorch/stable/), a deep learning framework for professional AI researchers and machine learning engineers who need maximal flexibility without sacrificing performance at scale;
+-  and [Lightning Fabric](https://lightning.ai/docs/fabric/stable/), a fast and lightweight way to scale PyTorch models without boilerplate).
+
+Please review the [bitsandbytes section in the PyTorch Lightning docs](https://lightning.ai/docs/pytorch/stable/common/precision_intermediate.html#quantization-via-bitsandbytes).
+
+
+# Lit-GPT
+
+Bitsandbytes is integrated into [Lit-GPT](https://github.com/Lightning-AI/lit-gpt), a hackable implementation of state-of-the-art open-source large language models, based on Lightning Fabric, where it can be used for quantization during training, finetuning, and inference.
+
+Please review the [bitsandbytes section in the Lit-GPT quantization docs](https://github.com/Lightning-AI/lit-gpt/blob/main/tutorials/quantize.md).
+
+
+
 # Trainer for the optimizers
 
 You can use any of the 8-bit and/or paged optimizers by simple passing them to the `transformers.Trainer` class on initialization.All bnb optimizers are supported by passing the correct string in `TrainingArguments`'s `optim` attribute - e.g. (`paged_adamw_32bit`).