diff --git a/apiserver/apiserver/api/models.py b/apiserver/apiserver/api/models.py
index 6fe3a47..134214e 100644
--- a/apiserver/apiserver/api/models.py
+++ b/apiserver/apiserver/api/models.py
@@ -172,10 +172,12 @@ class Usage(models.Model):
 
     device = models.CharField(max_length=64)
     start_time = models.DateTimeField(auto_now_add=True)
-    last_update = models.DateTimeField(auto_now=True)
+    updated_at = models.DateTimeField(auto_now=True)
     num_seconds = models.IntegerField()
+    memo = models.TextField(blank=True)
+    should_bill = models.BooleanField(default=True)
 
-    history = HistoricalRecords(excluded_fields=['num_seconds'])
+    history = HistoricalRecords(excluded_fields=['num_seconds', 'updated_at'])
 
 class HistoryIndex(models.Model):
     content_type = models.ForeignKey(ContentType, null=True, on_delete=models.SET_NULL)
diff --git a/apiserver/apiserver/api/views.py b/apiserver/apiserver/api/views.py
index d6e17cb..e12284f 100644
--- a/apiserver/apiserver/api/views.py
+++ b/apiserver/apiserver/api/views.py
@@ -663,6 +663,7 @@ class StatsViewSet(viewsets.ViewSet, List):
                 username=username,
                 device=device,
                 num_seconds=0,
+                memo='',
             )
             logging.info('New %s session created for: %s', device, username or '[no username]')