introduce Controller model
diff --git a/planetstack/core/models/node.py b/planetstack/core/models/node.py
index 9271268..903c25f 100644
--- a/planetstack/core/models/node.py
+++ b/planetstack/core/models/node.py
@@ -1,7 +1,7 @@
 import os
 from django.db import models
 from core.models import PlCoreBase
-from core.models import Site,Deployment
+from core.models import SiteDeployment, Controller
 from core.models import Tag
 from django.contrib.contenttypes import generic
 
@@ -9,8 +9,7 @@
 
 class Node(PlCoreBase):
     name = models.CharField(max_length=200, unique=True, help_text="Name of the Node")
-    site  = models.ForeignKey(Site, related_name='nodes')
-    deployment = models.ForeignKey(Deployment, related_name='nodes')
+    site_deployment = models.ForeignKey(SiteDeployment, related_name='nodes')
     tags = generic.GenericRelation(Tag)
 
     def __unicode__(self):  return u'%s' % (self.name)