title: irb history not working
body: <p>in ~/.irbrc i have these lines:</p>
  
  <pre><code>require 'irb/ext/save-history'
  #History configuration
  IRB.conf[:SAVE_HISTORY] = 100
  IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history"
  </code></pre>
  
  <p>and yet when i run <code>irb</code> and hit the up arrow nothing happens. also the irb history file specified is not getting created and nothing is logged to it. </p>