gistfile1.scala

  val bonusForm = Form(
    mapping(
      "alias" -> optional(text),
      "selectedBonus" -> optional(mapping(
        "itemId" -> nonEmptyText,
        "bonus" -> number
      )(Bonus.apply)(Bonus.unapply)),
      "bonuses" -> list(
        mapping(
          "itemId" -> nonEmptyText,
          "bonus" -> number
        )(Bonus.apply)(Bonus.unapply)
      )
    )
      ((alias, selectedItem, bonuses) => BonusForm(alias, selectedItem, bonuses))
      ((bonus) => Some(bonus.alias, bonus.selectedBonus, bonus.bonuses))
  )

gistfile2.scala

            @repeat(bonusForm("bonuses")) { bonus =>
                @bonus
                <tr>
                    <td><span name="items[]"></span></td>
                    <td class="numeric"><span name="bonuses[]"></span></td>
                    <td class="single-control">
                        <a><span class="icon-edit"></span></a>
                        <a><span class="icon-remove"></span></a>
                    </td>
                </tr>
            }