<form class="form-signin" ng-submit="vm.signin(vm.username, vm.room)">
  <h2 class="form-signin-heading">Please sign in</h2>
  <div class="form-group">
    <label for="inputUsername">Username</label>
    <input
           id="inputUsername"
           class="form-control"
           type="text"
           ng-model="vm.username"
           required="true"
           placeholder="A creative username.">
  </div>
  <div class="form-group">
    <label for="inputRoom">Room</label>
    <select
      id="inputRoom"
      class="form-control"
      ng-model="vm.room"
      required="true"
      ng-options="room.label for room in vm.rooms">
    </select>
  </div>
  <button class="btn btn-lg btn-primary btn-block" type="submit">Sign in</button>
</form>

<form class="form-signin" ng-submit="vm.signin(vm.username, vm.room)">
  <h2 class="form-signin-heading">Please sign in</h2>
  <div class="form-group">
    <label for="inputUsername">Username</label>
    <input
           id="inputUsername"
           class="form-control"
           type="text"
           ng-model="vm.username"
           required="true">
  </div>
  <div class="form-group">
    <label for="inputRoom">Room</label>
    <select
      id="inputRoom"
      class="form-control"
      ng-model="vm.room"
      required="true"
      ng-options="room.label for room in vm.rooms">
    </select>
  </div>
  <button class="btn btn-lg btn-primary btn-block" type="submit">Sign in</button>
</form>

Remove placeholder for username in sign-in form
Remove placeholder for username in sign-in form
