title: Rails - How do you insert a variable into a regular expression (Regex) for instance assert_match
body: <p>I want to do something like</p>
  
  <pre><code>assert_match /blah blah blah #{@user}/, @some_text
  </code></pre>
  
  <p>but I'm not having any luck with it working.</p>
  
  <p>What am I doing wrong here?</p>