update task functionality

frontend/allowance-planner-v2/src/app/pages/edit-task/edit-task.page.ts

@@ -45,8 +45,8 @@ export class EditTaskPage implements OnInit {
         this.form.setValue({
           name: task.name,
           reward: task.reward,
-          assigned: task.assigned
-        })
+          assigned: task.assigned !== null ? task.assigned : 0
+        });
       });
     }
   }
@@ -66,7 +66,9 @@ export class EditTaskPage implements OnInit {
 
     if (this.isAddMode) {
       this.taskService.createTask(task);
-    } else {}
+    } else {
+      this.taskService.updateTask(this.id, task);
+    }
 
     this.router.navigate(['/tabs/tasks']);
   }