add ruby example

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@12180 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/esl/ruby/single_command.rb

+#! /usr/bin/ruby
+
+require "ESL"
+
+command = ARGV.join(" ")
+con = ESL::ESLconnection.new("localhost", "8021", "ClueCon")
+e = con.sendRecv("api #{command}")
+puts e.getBody()