Template.persons.helpers({
  people: function(){
    var people = People.find({}).fetch(); // People is a Collection
    return people
  },
  selectedPerson: function(){
    if(this._id === Session.get("SelectedPerson")._id)
      return "alert alert-info"
  }
});

Template.persons.events({
  "click .person-detail-alert": function(event, template){
    var person = this;
    alert("You clicked "+ person.name);
    Session.set("SelectedPerson", person);
  }
})