Adding filter for tasks without a predecessor

http://localhost:8000/atdb/tasks/?predecessor__isnull=True

atdb/taskdatabase/templates/taskdatabase/index.html

@@ -80,7 +80,7 @@
         {% include 'taskdatabase/pagination.html' %}
        </div>
     </div>
-    <p class="footer"> Version 1.0.0 (28 oct 2021 - 11:30)
+    <p class="footer"> Version 1.0.0 (28 oct 2021 - 14:00)
 
 </div>
 

atdb/taskdatabase/views.py

@@ -55,6 +55,8 @@ class TaskFilter(filters.FilterSet):
             'purge_policy': ['exact'],
             'priority': ['exact','lte','gte'],
             'resume': ['exact'],
+            # http://localhost:8000/atdb/tasks/?predecessor__isnull=True
+            'predecessor': ['isnull'],
             'predecessor__status': ['exact', 'icontains', 'in', 'startswith'],
         }