title: Editing a .rb file under rails console
body: <p>I am trying to edit a <code>.rb</code> file with rails.</p>
  
  <p>So I enter:</p>
  
  <pre><code> $ rails c
   irb(main):001:0&gt; require config/application.rb
  </code></pre>
  
  <p>and then I get the following error message :</p>
  
  <blockquote>
    <p>NameEror: undefined local variable or method `config' for main:Object from (irb):1</p>
  </blockquote>
  
  <p>What am I doing wrong?</p>