Make it possible to select favourites events

Make it possible for users to select events which they want to see in the public schedule and in the All events section of the public schedule.

app/assets/javascripts/osem-schedule.js

@@ -1,3 +1,5 @@
+// ADMIN SCHEDULE
+
 var url; // Should be initialize in Schedule.initialize
 var schedule_id; // Should be initialize in Schedule.initialize
 
@@ -117,6 +119,34 @@ $(document).ready( function() {
   });
 });
 
+
+// PUBLIC SCHEDULE
+
+function starClicked(e){
+  // stops the click from propagating
+  if (!e) var e = window.event;
+  e.preventDefault();
+  e.cancelBubble = true;
+  if (e.stopPropagation) e.stopPropagation();
+
+  var callback = function(data) {
+    $(e.target).toggleClass('fa-star fa-star-o');
+  }
+
+  var params = { favourite_user_id: $(e.target).data('user') };
+  if($(e.target).hasClass('fa-star-o')){
+    params['add'] = true;
+  }
+
+  $.ajax({
+    url: $(e.target).data('url'),
+    type: 'PATCH',
+    data: params,
+    success: callback,
+    dataType : 'json'
+  });
+}
+
 function eventClicked(e, element){
   var url = $(element).data('url');
   if(e.ctrlKey)