Ability to cluster multiple servers together with one backing mongo instances

Cluster multiple servers together.

Some ideas:

1. Create table with active nodes. When a new node is added, pull the list, and create a socket.io connection to the other active nodes.
2. If a heart beat fails 2 times for a socket connection, rebalance the polling.
   http://stackoverflow.com/questions/18907591/socket-io-server-performance-and-bandwidth-usage for network usage.