Fix TODO before resetting migration

coin/reverse_dns/models.py

@@ -22,8 +22,7 @@ class NameServer(models.Model):
     description = models.CharField(max_length=255, blank=True,
                                    verbose_name="human-readable name of the nameserver",
                                    help_text="Example: My first name server")
-    # TODO: don't allow NULL owner (this is only here to allow migrations)
-    owner = models.ForeignKey("members.Member", null=True)
+    owner = models.ForeignKey("members.Member")
 
     def __unicode__(self):
         return "{} ({})".format(self.description, self.dns_name) if self.description else self.dns_name