Add sample rabl file

samples/ruby/rabl.rabl

@@ -0,0 +1,16 @@
+object @user => :person
+
+attributes :username, :email, :location
+attributes :created_at => :registered_at
+
+node :role do |user|
+  user.is_admin ? 'admin' : 'normal'
+end
+
+child :phone_numbers => :pnumbers do
+  extends "users/phone_number"
+end
+
+node :node_numbers do |u|
+  partial("users/phone_number", :object => u.phone_numbers)
+end