Fixes #1508: Enabled creating custom fields for clusters and virtual machines via the admin UI

netbox/extras/constants.py

@@ -3,10 +3,11 @@ from __future__ import unicode_literals
 
 # Models which support custom fields
 CUSTOMFIELD_MODELS = (
+    'provider', 'circuit',                                  # Circuits
     'site', 'rack', 'devicetype', 'device',                 # DCIM
     'aggregate', 'prefix', 'ipaddress', 'vlan', 'vrf',      # IPAM
-    'provider', 'circuit',                                  # Circuits
-    'tenant',                                               # Tenants
+    'tenant',                                               # Tenancy
+    'cluster', 'virtualmachine',                            # Virtualization
 )
 
 # Custom field types