If there are no track names for today, don't show the row

If there are track names today, show the row for track names. If there aren't, don't show an empty row.

pinaxcon/templates/symposion/schedule/_grid.html

@@ -7,6 +7,8 @@
           <th>{{ room.name }}</th>
           {% endfor %}
     </tr>
+    {% with timetable|day_has_tracks:timetable.day as has_tracks %}
+      {% if has_tracks %}
         <tr>
           <th class="time">&nbsp;</th>
           {% for room in timetable.rooms %}
@@ -15,6 +17,8 @@
 	        {% endwith %}
           {% endfor %}
         </tr>
+      {% endif %}
+    {% endwith %}
   </thead>
   <tbody>
     {% for row in timetable %}

pinaxcon/templatetags/lca2018_tags.py

@@ -78,6 +78,14 @@ def gst(amount):
 def conference_name():
     return conference_models.Conference.objects.get(id=CONFERENCE_ID).title
 
+@register.filter()
+def day_has_tracks(timetable, day):
+    try:
+        track_names = day.track_set.all()
+        has_tracks = True
+    except Track.DoesNotExist:
+        has_tracks = False
+    return len(track_names)
 
 @register.filter()
 def trackname(room, day):