title: How do I change the default gemfile created with 'rails new' command?
body: <p>I have recently experienced an issue where I must add the following to my gemfile:</p>
  
  <pre><code>gem 'execjs'
  gem 'therubyracer'
  </code></pre>
  
  <p>I must do this to avoid a javascript runtime error that occurs when starting the rails server.  I would like to have this modification added to all new gemfiles created with the rails new command.</p>