Add 'Image Upload' Feature

Each user can upload image to the system. The images from different users where be separated.

templates/index.html

@@ -13,6 +13,7 @@
         <li>Integrating with Bootstrap</li>
         <li>Interaction with Database (SQLite)</li>
         <li>Invoking static resources</li>
+        <li>Upload files</li>
     </ul>
 
     <p>For more basic knowledge of Flask, you can refer to <a href="https://www.tutorialspoint.com/flask/">a tutorial on Tutorialspoint</a>.</p>