Resolve "Add QR code scanning to person-group view"

Closes #40 (closed)

aleksis/apps/paweljong/templates/paweljong/event/persons_group.html

@@ -15,6 +15,7 @@
     {% form form=form %}{% form %}
     {% include "core/partials/save_button.html" %}
   </form>
+  <div id="qr-reader" data-target-input="username"></div>
   {{ form.media.js }}
 
 {% endblock %}