code: function setActiveUser (user) {
      var button = $('<button>')
                      .addClass ('btn btn-default')
                      .attr ('data-toggle', 'tooltip')
                      .attr ('data-placement', 'bottom')
                      .attr ('title', user.id)
                      .attr ('id', 'active-user-' + user.id)
                      .html ('<span class="glyphicon glyphicon-user" aria-hidden="true"></span>')
                      .css  ('color', user.color);
  
      $('#active-users-indicator').append (button);
      $('[data-toggle="tooltip"]').tooltip ({
        container: 'body'
      });
    }
docs: /*
  Adds the user to the active users container --
  -- indicates all users who are currently in the room.