Show trip nights

Closes: #119

templates/navbar.html

@@ -29,6 +29,9 @@
         </li>
         {% endfor %}
       </ul>
+      <ul class="navbar-nav ms-auto">
+        <li class="nav-item"><a class="nav-link" href="{{ config.UNIAUTH_URL }}/logout?next={{ request.url | urlencode }}">Logout</a></li>
+      </ul>
     </div>
   </div>
 </nav>

templates/trip_page.html

@@ -57,7 +57,10 @@
   <h1>{{ trip.title }}<small class="text-muted">({{ display_date(trip.start) }})</small></h1>
   <div>Countries: {{ trip.countries_str }}</div>
   {% if end %}
-    <div>Dates: {{ display_date_no_year(trip.start) }} to {{ display_date_no_year(end) }}</div>
+    <div>
+    Dates: {{ display_date_no_year(trip.start) }} to {{ display_date_no_year(end) }}
+    ({{ (end - trip.start).days }} nights)
+    </div>
   {% else %}
     <div>Start: {{ display_date_no_year(trip.start) }} (end date missing)</div>
   {% endif %}