merge latest Amisha changes
diff --git a/planetstack/core/models/slice.py b/planetstack/core/models/slice.py
index 86a1586..94bcd5b 100644
--- a/planetstack/core/models/slice.py
+++ b/planetstack/core/models/slice.py
@@ -20,10 +20,10 @@
     description=models.TextField(blank=True,help_text="High level description of the slice and expected activities", max_length=1024)
     slice_url = models.URLField(blank=True, max_length=512)
     site = models.ForeignKey(Site, related_name='slices', help_text="The Site this Slice belongs to")
-    imagePreference = models.CharField(default="abc",null=True, blank=True, max_length=256)
+    imagePreference = models.CharField(null=True, blank=True, max_length=256)
     service = models.ForeignKey(Service, related_name='service', null=True, blank=True)
-    network = models.CharField(null=True, blank=True, max_length=256)
-    mountDataSets = models.CharField(null=True, blank=True, max_length=256)
+    network = models.CharField(default="Private Only",null=True, blank=True, max_length=256)
+    mountDataSets = models.CharField(default="GenBank",null=True, blank=True, max_length=256)
     tags = generic.GenericRelation(Tag)
 
     serviceClass = models.ForeignKey(ServiceClass, related_name = "slices", null=True, default=ServiceClass.get_default)