Determine registry schema

[spencergibb]

Currently <hostname>:<port> is all that is stored in etcd. It could probably a little bit richer, possibly a json document.

[spencergibb]

see #20

[marcingasior]

@spencergibb Hi Spencer,

Can you elaborate a bit more about your ideas on this?

Are you looking for something like?

{
  "key":"sample key",
  "value": "some value",
  "attributes": {
      //whatever you like to put, with some size limits like eg.8096 bytes
  }
}

Or something more concrete?

[spencergibb]

What data should be there, not just the format. Right now we have host/port. Eureka has a lot. Here's consul and zookeeper