Start working on a etcd backend

middleware/etcd/etcd.md

@@ -0,0 +1,26 @@
+# etcd
+
+`etcd` enabled reading zone data from an etcd instance. The data in etcd has to be encoded as
+a [message](https://github.com/skynetservices/skydns/blob/2fcff74cdc9f9a7dd64189a447ef27ac354b725f/msg/service.go#L26)
+like SkyDNS.
+
+## Syntax
+
+~~~
+etcd [address...]
+~~~
+
+* `address` is the endpoint of etcd.
+
+The will default to `/skydns` as the path and the local etcd proxy (http://127.0.0.1:2379).
+
+~~~
+etcd {
+    round_robin
+    path /skydns
+    address address...
+    stubzones
+}
+~~~
+
+## Examples