Merge branch 'hotfix/install-in-jumbotron'

Close #300

Author: weierophinney

doc/book/index.html

@@ -3,6 +3,8 @@
     <h1>Expressive</h1>
 
     <p>PSR-7 Middleware in Minutes</p>
+
+    <pre><code class="language-bash">$ composer create-project -s rc zendframework/zend-expressive-skeleton expressive</code></pre>
   </div>
 </div>