Added Github Star badge instead of dummy badge and github link (#144)

website/core/Footer.js

@@ -49,17 +49,7 @@ class Footer extends React.Component {
           </div>
           <div>
             <h5>More</h5>
-            <a href="https://github.com/mingrammer/diagrams">GitHub</a>
-            <a
-              className="github-button"
-              href={this.props.config.repoUrl}
-              data-icon="octicon-star"
-              data-count-href="/mingrammer/diagrams/stargazers"
-              data-show-count="true"
-              data-count-aria-label="# stargazers on GitHub"
-              aria-label="Star this project on GitHub">
-              Star
-            </a>
+            <iframe src="https://ghbtns.com/github-btn.html?user=mingrammer&repo=diagrams&type=star&count=true&size=large" frameBorder="0" scrolling="0" width="170" height="30" title="Star mingrammer/diagrams on GitHub"></iframe>
           </div>
         </section>
         <section className="copyright">{this.props.config.copyright}</section>