title: converting Time class object to RFC3339 in Ruby
body: <p><a href="https://developers.google.com/google-apps/calendar/v2/developers_guide_protocol" rel="noreferrer">Google Calendar API(v2)</a>'s time-related query is required to be RFC3339-formatted. When I looked up Time class after 'require "time"', I could not see rfc3339 method.</p>