Explained that you need to create your app in a new directory

See jhipster/generator-jhipster#1368

Author: jdubois

creating_an_app.html

@@ -10,6 +10,19 @@ <h1><i class="fa fa-rocket"></i> Creating an application</h1>
 
 <i><b>Please check our <a href="{{ site.url }}/video_tutorial.html">video tutorial</a> on creating a new JHipster application!</b></i>
 <h2>Generating an application quickly</h2>
+
+<p>First of all, create an empty directory in which you will create your application:</p>
+<p>
+<code>
+    mkdir myapplication
+</code>
+</p>
+<p>Go to that directory:</p>
+<p>
+<code>
+    cd myapplication/
+</code>
+</p>
 <p>To generate your application, type:</p>
 <p>
 <code>
@@ -54,7 +67,7 @@ <h3>Which *type* of authentication would you like to use?</h3>
 
 <h3>Which *type* of database would you like to use?</h3>
 <p>
-  You can choose between a classical SQL database, which you will access with Spring Data JPA, or a NoSQL approach with <a href="http://www.mongodb.org" target="_blank">MongoDB</a>.
+  You can choose between a classical SQL database, which you will access with Spring Data JPA, or a NoSQL approach with <a href="http://www.mongodb.org" target="_blank">MongoDB</a> or <a href="http://cassandra.apache.org/" target="_blank">Cassandra</a>.
 </p>
 
 <h3>Which *production* database would you like to use?</h3>