title: Appending to an existing string
body: <p>To append to an existing string this is what I am doing.</p>
  
  <pre><code>s = 'hello'
  s.gsub!(/$/, ' world');
  </code></pre>
  
  <p>Is there a better way to append to an existing string.</p>
  
  <p>Before someone suggests following answer lemme show that this one does not work</p>
  
  <pre><code>s = 'hello'
  s.object_id
  s = s + ' world'
  s.object_id 
  </code></pre>
  
  <p>In the above case object_id will be different for two cases.</p>