Add backbone checks.

lms/static/coffee/src/discussion/discussion_router.coffee

-class @DiscussionRouter extends Backbone.Router
+if Backbone?
+  class @DiscussionRouter extends Backbone.Router
     routes:
       "": "allThreads"
       ":forum_name/threads/:thread_id" : "showThread"

lms/static/coffee/src/discussion/main.coffee

-DiscussionApp =
+if Backbone?
+  DiscussionApp =
     start: (elem)->
       # TODO: Perhaps eliminate usage of global variables when possible
       element = $(elem)
@@ -12,6 +13,6 @@ DiscussionApp =
       new DiscussionRouter({discussion: discussion})
       Backbone.history.start({pushState: true, root: "/courses/#{$$course_id}/discussion/forum/"})
 
-$ ->
+  $ ->
     $("section.discussion").each (index, elem) ->
       DiscussionApp.start(elem)

lms/static/coffee/src/discussion/models/discussion_user.coffee

-class @DiscussionUser extends Backbone.Model
+if Backbone?
+  class @DiscussionUser extends Backbone.Model
       following: (thread) ->
           _.include(@get('subscribed_thread_ids'), thread.id)
 

lms/static/coffee/src/discussion/user_profile.coffee

-class @DiscussionUserProfileView extends Backbone.View
+if Backbone?
+  class @DiscussionUserProfileView extends Backbone.View
     toggleModeratorStatus: (event) ->
       confirmValue = confirm("Are you sure?")
       if not confirmValue then return

lms/static/coffee/src/discussion/views/discussion_content_view.coffee

-class @DiscussionContentView extends Backbone.View
+if Backbone?
+  class @DiscussionContentView extends Backbone.View
 
     attrRenderer:
       endorsed: (endorsed) ->

lms/static/coffee/src/discussion/views/discussion_thread_inline_view.coffee

-class @DiscussionThreadInlineView extends DiscussionContentView
+if Backbone?
+  class @DiscussionThreadInlineView extends DiscussionContentView
     expanded = false
     events:
       "click .discussion-vote": "toggleVote"

lms/static/coffee/src/discussion/views/discussion_thread_list_view.coffee

-class @DiscussionThreadListView extends Backbone.View
+if Backbone?
+  class @DiscussionThreadListView extends Backbone.View
     template: _.template($("#thread-list-template").html())
     events:
       "click .search": "showSearch"
@@ -263,7 +264,3 @@ class @DiscussionThreadListView extends Backbone.View
       scrollTarget = Math.min(scrollTop - itemFromTop, scrollTop)
       scrollTarget = Math.max(scrollTop - itemFromTop - $(".browse-topic-drop-menu").height() + $(items[index]).height(), scrollTarget)
       $(".browse-topic-drop-menu").scrollTop(scrollTarget)
-
-
-
-

lms/static/coffee/src/discussion/views/discussion_thread_view.coffee

-class @DiscussionThreadView extends DiscussionContentView
+if Backbone?
+  class @DiscussionThreadView extends DiscussionContentView
 
     events:
       "click .discussion-submit-post": "submitComment"

lms/static/coffee/src/discussion/views/new_post_inline_vew.coffee

-class @NewPostInlineView extends Backbone.View
+if Backbone?
+  class @NewPostInlineView extends Backbone.View
 
     initialize: () ->
 

lms/static/coffee/src/discussion/views/new_post_view.coffee

-class @NewPostView extends Backbone.View
+if Backbone?
+  class @NewPostView extends Backbone.View
 
       initialize: () ->
           @dropdownButton = @$(".topic_dropdown_button")

lms/static/coffee/src/discussion/views/response_comment_view.coffee

-class @ResponseCommentView extends DiscussionContentView
+if Backbone?
+  class @ResponseCommentView extends DiscussionContentView
     tagName: "li"
     template: _.template($("#response-comment-template").html())
     initLocal: ->

lms/static/coffee/src/discussion/views/thread_response_view.coffee

-class @ThreadResponseView extends DiscussionContentView
+if Backbone?
+  class @ThreadResponseView extends DiscussionContentView
     tagName: "li"
     template: _.template($("#thread-response-template").html())