title: Ruby: Testing a ruby string for a substring fails (substring is not recognized)
body: <p>Using Ruby, I am trying to weed out spam messages the manual way, so why exactly does the below test return <code>false</code> when it should return <code>true</code>? The tested string is the <em>original</em> one, so you can literally copy/paste the whole thing into your ruby console to verify this example:</p>
  
  <pre><code>irb(main):053:0&gt; "Веautiful women fоr sеx in yоur town АU: https://links.wtf/qLFs".include? "sex"
  =&gt; false
  </code></pre>
  
  <p>Hint: If you replace the word "sex" inside the entire string by typing it in yourself, the test will return <code>true</code> as expected. So, somehow, the two "sex" strings are not the same, but on what level? How to test that correctly?</p>
  
  <p><em>EDIT</em>:</p>
  
  <p>I have narrowed it all down to this (copy/paste it to test it!):</p>
  
  <pre><code>irb(main):073:0&gt; "е" == "e"
  =&gt; false
  </code></pre>