the thing thats troubling me now is how to pass the date in to the scope in the jbuilder without hardcoding it 

json.array!(@leave_events) do |leave_event|
  json.extract! leave_event, :id, :user_id, :team_id
  json.start leave_event.start_time
  json.end leave_event.end_time
  json.events_on_date LeaveEvent.events_on_date(date) // this line is where I can figure out stuff 
  json.max_allowable_leave leave_event.team.max_allowable_leave
end

see the rest of `calendar.js`

$(document).ready(function() {
  return $("#calendar").fullCalendar({
    header: {
      left: 'title',
      center: 'agendaDay,agendaWeek,month',
      right: 'today prev,next',
    },
    weekends: false,
    events: '/leave_events.json',
    eventLimit: 1,
    dayRender: function( date, cell ) {
      var events_on_date = ;
      $.getJSON('leave_events.json', function(json) {
        for (var i = 0; i < json.length; i++) {
          console.log(events_on_date);
          if (events_on_date > json[0].max_allowable_leave){
            cell.css("background-color", "red");
          }
        }
      });
      if (moment().diff(date,'days') > 0){
        cell.css("background-color", "silver");
      }
    }
  });
});