title: How to display all instances of a model in Rails?
body: <p>In my web application the user can select certain instances of an entity. For instance on the class <code>BubbleGum</code>, now the user can select certain instances of <code>BubbleGum</code> by adressing their identifier:</p>
  
  <pre><code>gums/details?show=3532667
  </code></pre>
  
  <p>Now, in addition I also want to make it possible to display all <code>BubbleGums</code>. For this I have introduced the convention of using <code>*</code> to identify all</p>
  
  <pre><code>gums/details?show=*
  </code></pre>
  
  <p>This works nice so far, but often I have to add a bit code to process the <code>*</code> selection. Is there a nice way to represent an <strong>all-instances</strong> object in Ruby and/or Rails?</p>
  
  <p>I have thought of using simply a dedicated symbol, constants, or an actual object of the class <code>BubbleGum</code> that represents all the other bubble gums.</p>