Add first contributions in Basics section

First contributions is a project to help beginners to get started with contributing to open source projects.

We have a hands-on tutorial, a web app to find projects to contribute to and a slack community to ask questions and get help.

Here's a code snippet that could go in to opensourcediversity.org

<a class="col-md-4" href="https://firstcontributions.github.io" target="_blank" rel="noopener">
	<img alt="" src="https://avatars1.githubusercontent.com/u/37713493?v=4" />
	<h3>First Contributions</h3>
	<p>🚀✨ Help beginners to contribute to open source projects </p>
</a>