evaluate default for plcorebase.created and plcorebase.updated at time of model creation rather than when python file is loaded
diff --git a/planetstack/core/models/plcorebase.py b/planetstack/core/models/plcorebase.py
index 606ea85..59cac52 100644
--- a/planetstack/core/models/plcorebase.py
+++ b/planetstack/core/models/plcorebase.py
@@ -37,8 +37,8 @@
 
     # default values for created and updated are only there to keep evolution
     # from failing.
-    created = models.DateTimeField(auto_now_add=True, default=datetime.datetime.now())
-    updated = models.DateTimeField(auto_now=True, default=datetime.datetime.now())
+    created = models.DateTimeField(auto_now_add=True, default=datetime.datetime.now)
+    updated = models.DateTimeField(auto_now=True, default=datetime.datetime.now)
     enacted = models.DateTimeField(null=True, default=None)
     backend_status = models.CharField(max_length=140,
                                       default="Provisioning in progress")