Update Readme with signup link

Author: fvonhoven

README.md

@@ -2,6 +2,25 @@
 
 Free bi-weekly summary of React Native news, articles, issues & pull requests, libraries and apps curated by Frank von Hoven ([@infinite_frank](https://twitter.com/infinite_frank)).
 
-## [Sign up here!](http://reactnative.cc)
+<!-- Begin Mailchimp Signup Form -->
+<link href="//cdn-images.mailchimp.com/embedcode/horizontal-slim-10_7.css" rel="stylesheet" type="text/css">
+<style type="text/css">
+	#mc_embed_signup{background:#fff; clear:left; font:14px Helvetica,Arial,sans-serif; width:100%;}
+	/* Add your own Mailchimp form style overrides in your site stylesheet or in this style block.
+	   We recommend moving this block and the preceding CSS link to the HEAD of your HTML file. */
+</style>
+<div id="mc_embed_signup">
+<form action="https://reactnative.us10.list-manage.com/subscribe/post?u=db0dd948e2b729ee62625b1a8&amp;id=47cd41008f" method="post" id="mc-embedded-subscribe-form" name="mc-embedded-subscribe-form" class="validate" target="_blank" novalidate>
+    <div id="mc_embed_signup_scroll">
+	<label for="mce-EMAIL">Subscribe to the React Native Newsletter</label>
+	<input type="email" value="" name="EMAIL" class="email" id="mce-EMAIL" placeholder="email address" required>
+    <!-- real people should not fill this in and expect good things - do not remove this or risk form bot signups-->
+    <div style="position: absolute; left: -5000px;" aria-hidden="true"><input type="text" name="b_db0dd948e2b729ee62625b1a8_47cd41008f" tabindex="-1" value=""></div>
+    <div class="clear"><input type="submit" value="Subscribe" name="subscribe" id="mc-embedded-subscribe" class="button"></div>
+    </div>
+</form>
+</div>
+
+<!--End mc_embed_signup-->
 
 ## [Past Issues](http://reactnative.cc/issues.html)