Add sharing question and answer.

website/info/faq.html

@@ -109,6 +109,21 @@
             </p>
         </div>
 
+		<h2>Model Share</h2>
+
+        <h3 class="question">Why does sharing fail?</h3>
+		<div class="answer">
+            <p>
+                Online 3D Viewer doesn't store models, everything happens in your browser. Sharing possible only if your
+                files are coming from an external server. For example you can share a model that is loaded using the
+                open url button (<i class="icon icon-open_url"></i>).
+            </p>
+            <p>
+                When you drag and drop a model, or load it using the open button (<i class="icon icon-open"></i>), the model
+                is not publicly available, so in this case sharing is not possible.
+            </p>
+        </div>
+
 	</div>
 </body>