title: Finding "Next Tuesday" in Ruby
body: <pre><code>require 'active_support/all'
  days = 0.day.ago
  days += 1 until days.since.wday == 2 
  next_tuesday = days.since
  </code></pre>
  
  <p>Above code is not doing right. But below is right. Could you tell me why?</p>
  
  <pre><code>require 'active_support/all'
  current_day = 0.day.ago
  current_day += 1.day until current_day.wday == 2
  next_tuesday = current_day
  </code></pre>