title: NameError: uninitialized constant Song ...Programming Ruby
body: <p>trying to pick up ruby through this programming ruby site and i'm stuck on this syntax</p>
  
  <pre><code>class SongList
  
  
    def initialize
      @songs = Array.new
    end
  
    def append(aSong)
      @songs.push(aSong)
      self
    end
  
  
    def deleteFirst
      @songs.shift
    end
    def deleteLast
      @songs.pop
    end
  
  
  end
  </code></pre>
  
  <p>When i go to add a song...</p>
  
  <pre><code>list = SongList.new
  list.append(Song.new('title1', 'artist1', 1))
  </code></pre>
  
  <p>I get this error message: </p>
  
  <pre><code>NameError: uninitialized constant Song ...Programming Ruby 
  </code></pre>
  
  <p>I saw that i need to require the variable Song, but I'm not sure where to do it within the SongList class....</p>