Integration and loading public holiday from Google Calendar into Fullcalendar rails4

Integrate Google Calendar XML resource into fullcalendar

1. Add rails4 Fullcalendar gem to Gemfile
    gem 'fullcalendar-rails'
  Then run command:  bundle install
  
2. Copy & pasted into assets/stylesheet/application.css.scss (By default  application.css, so just rename)
    *= require fullcalendar

3. Copy & pasted into assets/javascript/application.js
    //= require fullcalendar
    //= require gcal 
4. then create a new view and put a tag
    %div#fullcalendar
    
5. Put this script into the same view
    
      :javascript
        // defined instance of the dialog
        $( "#dialog" ).dialog( { 
            autoOpen: false, 
            title: "Input Holiday"
            });

        // user click, then dialog popup
        $('#calendar').fullCalendar({
            header: {
              right: "prev,next, today",
              center: "title",
              left: "month,agendaWeek,agendaDay"
            },
            events: {
              url: 'https://www.google.com/calendar/feeds/en.cambodian%23holiday%40group.v.calendar.google.com/public/basic'
            },
            eventSources: [{
              url: "/posts",
            }],
            dayClick: function() {
              $('#dialog').dialog("open");
            },
            theme: true,
            height: 600,
        });