Votes.js, add a voting count to Teambox

gistfile1.js

/**
 * Adds a Like button to tasks, so users can like them.
 *
 * By default there are no votes enabled in the project. To enable:
 *
 *   project.metadata('apps').set({ votes: true });
 *   project.metadata('apps').save();
 *
 */

(function () {

  function addVoteCounter(view) {
    var task = view.model, voted_by, $vote;

    // If this project doesn't have votes enabled, skip
    if (!task.rel('project').metadata('apps').get('votes')) {
      return;
    }

    voted_by = task.metadata('votes').get('voted_by') || [];

    // Insert vote element
    $vote = $("<div class='js-vote vote_counter'><span class='icon-thumbs-up'></span></div>");
    $vote.append($("<span class='js-vote-count'>").text(voted_by.length));
    if (voted_by.indexOf(Teambox.models.user.id) !== -1) {
      $vote.addClass('voted');
    }
    $(view.el).find(".taskHeader .comment_count").before($vote);

    // Prepare click action
    $vote.unbind().click(function (evt) {
      evt.stopPropagation();

      // If not voted, vote. If voted, unvote
      if (voted_by.indexOf(Teambox.models.user.id) === -1) {
        voted_by = _(voted_by.concat(Teambox.models.user.id)).uniq();
      } else {
        voted_by = _(voted_by).chain().reject(function (id) {
          return id === Teambox.models.user.id;
        }).uniq().value();
      }

      // Persist
      task.metadata('votes').set({ 'voted_by': voted_by });
      task.metadata('votes').save();

      // Re-render
      view.renderHeader();
    });
  }

  $(function () {
    Teambox.Events.bind('sdk:task:render', addVoteCounter);
    Teambox.Events.bind('sdk:task:render:header', addVoteCounter);

    $.injectCss(".vote_counter { display: inline-block; position: relative; top: -2px; font-size: 11px; }");
    $.injectCss(".vote_counter span.icon-thumbs-up { font-size: 16px; }");
    $.injectCss(".vote_counter:hover { color: black; }");
    $.injectCss(".vote_counter.voted { color: #333; }");
  });

}());