title: String.equalsIgnoreCase(...) equivalent in Ruby
body: <p>I want to test 2 strings for equality in Ruby in a case insensitive manner. </p>
  
  <p>In languages, such as <a href="http://fantom-lang.org/" rel="nofollow noreferrer">Fantom</a>, you simply write:</p>
  
  <pre><code>string1.equalsIgnoreCase(string2)
  </code></pre>
  
  <p>What's the <em><strong>idiomatic</strong></em> way to do this in Ruby?</p>