title: Add element to specific index of list
body: <p>What is the best way of adding to a specific index of a list in scala? </p>
  
  <p>This is what I have tried: </p>
  
  <pre><code>case class Level(price: Double) 
  
  case class Order(levels: Seq[Level] = Seq())
  
  def process(order: Order) {
      orderBook.levels.updated(0, Level(0.0))
  }
  </code></pre>
  
  <p>I was hoping to insert into position zero the new <code>Level</code> but it just throws <code>java.lang.IndexOutOfBoundsException: 0</code> . What is the best way of handling this? Is there a better data type other than <code>Seq</code> which should be used for keeping track of indexes in a list?</p>