title: What does ':' stand for in Ruby On Rails?
body: <p>I am just beginning to learn Ruby and have the following code in a project:</p>
  
  <pre><code>USER_ATTRS = [:login, :password, :lastname, :firstname, :mail, :admin]
  </code></pre>
  
  <p>What does this do? Where do <code>:login</code> and all the other things come from?</p>
  
  <p>Are they just properties of a class (user, probably)?</p>
  
  <p>Can someone can help me out please? Because I can't really find this on the net.</p>