<h2>People you can challenge</h2>
<select class="ChallengeSelect form-control">
  {{#each this.challengeableUsers}}
        {{#if this.spotOpen}}
          <option value="{{this.spotId}} open">
            {{this.spotId}} (open)
          </option>
        {{else}}
          <option value="{{this.spotId}} {{this.name}}">
            {{this.spotId}}: {{this.name}}
          </option>
        {{/if}}
  {{/each}}
  <input type="submit" class="ChallengeSelect-submit btn btn-default" value="Challenge"/>
</select>
<script src="/public/js/challenges/challenge-select.js"></script>

<h2>People you can challenge</h2>
<select class="ChallengeSelect form-control">
  {{#each this.challengeableUsers}}
        {{#if this.spotOpen}}
          {{#unless this.challengeFull}}
            <option value="{{this.spotId}} open">
              {{this.spotId}} (open - challenged {{this.challengedCount}} time(s))
            </option>
          {{else}}
            <option disabled>
              {{this.spotId}} (open - challenged {{this.challengedCount}} time(s))
            </option>
          {{/unless}}
        {{else}}
          {{#unless this.challengeFull}}
            <option value="{{this.spotId}} {{this.name}}">
              {{this.spotId}}: {{this.name}}
            </option>
          {{else}}
            <option disabled>
              {{this.spotId}}: {{this.name}}
            </option>
          {{/unless}}
        {{/if}}
  {{/each}}
  <input type="submit" class="ChallengeSelect-submit btn btn-default" value="Challenge"/>
</select>
<script src="/public/js/challenges/challenge-select.js"></script>

Check for person challenged in select and disable if spot full
Check for person challenged in select and disable if spot full
