Display tags.

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

@@ -33,6 +33,9 @@ if Backbone?
       @main.render()
       @main.on "thread:responses:rendered", =>
         @nav.updateSidebar()
+      @main.on "tag:selected", (tag) =>
+        search = "[#{tag}]"
+        @nav.setAndSearchFor(search)
 
     navigateToThread: (thread_id) =>
       thread = @discussion.get(thread_id)

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

@@ -236,6 +236,11 @@ if Backbone?
         text = @$(".post-search-field").val()
         @searchFor(text)
 
+    setAndSearchFor: (text) ->
+      @showSearch()
+      @$(".post-search-field").val(text)
+      @searchFor(text)
+
     searchFor: (text, callback, value) ->
       @current_search = text
       url = DiscussionUtil.urlFor("search")

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

@@ -3,6 +3,7 @@ if Backbone?
 
     events:
       "click .discussion-submit-post": "submitComment"
+      "click .thread-tag": "tagSelected"
 
     $: (selector) ->
       @$el.find(selector)
@@ -19,6 +20,7 @@ if Backbone?
 
       @renderShowView()
       @renderAttrs()
+      @renderTags()
       @$("span.timeago").timeago()
       @makeWmdEditor "reply-body"
       @renderResponses()
@@ -28,6 +30,16 @@ if Backbone?
       if @responsesRequest?
         @responsesRequest.abort()
 
+    renderTags: ->
+      tags = $('<div class="thread-tags">')
+      for tag in @model.get("tags")
+        tags.append("<a class='thread-tag'>#{tag}</a>")
+      @$(".post-body").after(tags)
+
+    tagSelected: (e) ->
+      @trigger "tag:selected", $(e.target).html()
+
+
     renderResponses: ->      
       setTimeout(=>
         @$el.find(".loading").show()