title: Set default stage with Capistrano 3
body: <p>Is there a way to set a default stage in Capistrano 3?</p>
  
  <p>I've tried putting <code>set :stage, :production</code> inside deploy.rb but that didn't work, it gives the error:</p>
  
  <pre><code>Stage not set, please call something such as `cap production deploy`,
  where production is a stage you have defined
  </code></pre>
  
  <p>I only have one stage right now so I want to be able to just run <code>cap deploy</code> and have it execute on the default.</p>