[reposense#2061] Add contributors section to the README (reposense#2062)

The contributors of the project are not mentioned in the README. 

Let us add a contributors section so that the RepoSense community is
given credit for their contributions.

README.md

@@ -15,6 +15,10 @@ RepoSense is a contribution analysis tool for Git repositories. It is particular
   - [User Guide for the latest `master` (not yet released to users)](https://reposense.github.io/RepoSense)
 
 ---
+### Our Contributors :
+<a href="https://github.com/reposense/RepoSense/graphs/contributors">
+  <img src="https://contrib.rocks/image?repo=reposense/RepoSense" />
+</a>
 
 **Acknowledgements**: The web previews of RepoSense is powered by Netlify and Surge.