diff --git a/sylk/applications/webrtcgateway/models/storage/cassandra.py b/sylk/applications/webrtcgateway/models/storage/cassandra.py
index f7ec6aa..e655ad6 100644
--- a/sylk/applications/webrtcgateway/models/storage/cassandra.py
+++ b/sylk/applications/webrtcgateway/models/storage/cassandra.py
@@ -1,53 +1,54 @@
 
 from cassandra.cqlengine import columns
 from cassandra.cqlengine.models import Model
 
 
 class PushTokens(Model):
     __table_name__   = 'push_tokens'
     username         = columns.Text(partition_key=True)
     domain           = columns.Text(partition_key=True)
     device_id        = columns.Text(primary_key=True)
     app_id           = columns.Text(primary_key=True)
     background_token = columns.Text(required=False)
     device_token     = columns.Text()
     platform         = columns.Text()
     silent           = columns.Text()
     user_agent       = columns.Text(required=False)
 
 
 class ChatMessage(Model):
     __table_name__  = 'chat_messages_by_timestamp'
     __options__     = {'default_time_to_live': '31536000',
-                        'gc_grace_seconds': '345600'}
+                       'gc_grace_seconds': '345600'}
     account         = columns.Text(partition_key=True)
     contact         = columns.Text()
     created_at      = columns.DateTime(primary_key=True)
     direction       = columns.Text()
     message_id      = columns.Text(primary_key=True)
     content         = columns.Text()
     content_type    = columns.Text()
     disposition     = columns.List(value_type=columns.Text, required=False)
     state           = columns.Text()
     msg_timestamp   = columns.DateTime()
 
 
 class ChatMessageIdMapping(Model):
     __table_name__  = 'chat_message_created_at_by_id'
     __options__     = {'default_time_to_live': '31536000',
-                        'gc_grace_seconds': '345600'}
+                       'gc_grace_seconds': '345600'}
     message_id      = columns.Text(partition_key=True)
     created_at      = columns.DateTime()
 
 
 class PublicKey(Model):
     __table_name__   = 'public_key_by_account'
     public_key       = columns.Text()
     account          = columns.Text(partition_key=True)
+    created_at       = columns.DateTime()
 
 
 class ChatAccount(Model):
     __table_name__   = 'chat_accounts'
     account          = columns.Text(partition_key=True)
     api_token        = columns.Text()
     last_login       = columns.DateTime()