title: Ruby 'gem tzinfo'
body: <p>From my previous <a href="https://stackoverflow.com/questions/9828648/utc-time-timezones-daylight-savings-and-daylight-savings-switchover-dates">question about timezones</a>, I decided to use the Ruby gem tzinfo to get access to time zone data. This means storing scheduled times as a timezone name (e.g. "America/Toronto"), and then using the <a href="http://rubygems.org/gems/tzinfo" rel="nofollow noreferrer">Ruby  tzinfo gem</a> and <a href="http://www.iana.org/time-zones" rel="nofollow noreferrer">tzinfo database</a> to look up the correct UTC time from a desired local time. </p>
  
  <p>My understanding is that the database of time zones changes from time to time because different jurisdictions call for different policies on the (non)application of Daylight Savings Time. </p>
  
  <p>Once I install the Ruby gem tzinfo, how do I keep the time zone database up to date?</p>
  
  <p>Also, are time-zones ever dropped from the database?</p>