Add about section in settings (#134)

* About section in settings

* Added about section in settings tab

* fix code style

Co-authored-by: Sascha Ißbrücker <sascha.issbruecker@googlemail.com>

bookmarks/templates/settings/general.html

@@ -69,6 +69,15 @@
             {% endif %}
         </section>
 
+        {# About section #}
+        <section class="content-area">
+            <h2>About</h2>
+            <p>Version: {{ app_version }}</p>
+            <p>
+                Code: <a href="https://github.com/sissbruecker/linkding/"
+                    target="_blank">GitHub</a>
+            </p>
+        </section>
     </div>
 
 {% endblock %}