Added contributors and back to top (#304)

## Summary
<!--- This is a required section; please describe the main purpose of
this proposed code change. --->
Added the contributors section in the readme and also added the back to
top button.
<!---
## Details
This is an optional section; is there anything specific that reviewers
should be aware of?
--->

README.md

@@ -1,3 +1,5 @@
+<a name="readme-top"></a>
+
 # Liger Kernel: Efficient Triton Kernels for LLM Training
 
 
@@ -357,3 +359,15 @@ Biblatex entry:
 
 ## Star History
 [![Star History Chart](https://api.star-history.com/svg?repos=linkedin/Liger-Kernel&type=Date)](https://star-history.com/#linkedin/Liger-Kernel&Date)
+
+## Contributors
+
+<a href="https://github.com/linkedin/Liger-Kernel/graphs/contributors">
+  <img alt="contributors" src="https://contrib.rocks/image?repo=linkedin/Liger-Kernel"/>
+</a>
+
+<p align="right" style="font-size: 14px; color: #555; margin-top: 20px;">
+    <a href="#readme-top" style="text-decoration: none; color: #007bff; font-weight: bold;">
+        ↑ Back to Top ↑
+    </a>
+</p>