title: handing daily tasks in rails with timezones and DST
body: <p>In my app, users can select a time that they want to receive a daily email. I then regularly run a script to find users who have an upcoming email to send and send it. So, if users elect to have an email that goes out at 7AM, I look for users with that selected as their time and send it. </p>
  
  <p>The problem is of course timezones. I'm going to have users in different timezones and need 7AM to always be 7AM, regardless of timezones or daylight savings. </p>
  
  <p>I can understand how to do it for display purposes, but I can't find much info on executing queries that have to factor in the timezone and DST for a collection of users with varying times and timezones. </p>