Adding an example to the README

Author: Rafe Colton

README.md

@@ -4,3 +4,33 @@ ansible-module-etcd
 Ansible module for operating on etcd keys
 
 **TODO:** add tests
+
+Example playbook usage:
+
+```yaml
+---
+- hosts: '{{ server }}'
+  tasks:
+    - name: set value in etcd
+      etcd:
+        state: present
+        host: my-etcd-host.example.com
+        port: 4001
+        key: /asdf/foo/bar/baz/gorp
+        value: my-foo-bar-baz-gor-server.prod.example.com
+      delegate_to: localhost
+      connection: local
+      sudo: false
+
+    - name: get value from etcd
+      etcd:
+        state: retrieved
+        host: my-etcd-host.example.com
+        port: 4001
+        key: /asdf/foo/bar/baz/gorp
+      register: foo
+      delegate_to: localhost
+      connection: local
+      sudo: false
+      register: result # use result.value
+```