Add modal controller.

services/web/public/coffee/ide/review-panel/controllers/TrackChangesUpgradeModalController.coffee

@@ -0,0 +1,11 @@
+define [
+	"base"
+], (App) ->
+	App.controller "TrackChangesUpgradeModalController", ($scope, $modalInstance) ->
+		$scope.cancel = () ->
+			$modalInstance.dismiss()
+			
+		$scope.startFreeTrial = (source) ->
+			ga?('send', 'event', 'subscription-funnel', 'upgraded-free-trial', source)
+			window.open("/user/subscription/new?planCode=student_free_trial_7_days")
+			$scope.startedFreeTrial = true