Toggle show/hide chapters in textbook show view

cms/templates/js/textbook-show.underscore

 <li class="textbook">
     <span class="name"><%= name %></span>
     <% if(chapters.length > 1) {%>
-        <%= chapters.length %> PDF Chapters
+        <a href="#" class="chapter-toggle
+            <% if(showChapters){ print('hide'); } else { print('show'); } %>-chapters">
+            <i class="icon-chevron-<% if(showChapters){ print('down'); } else { print('right'); } %>"></i>
+            <%= chapters.length %> PDF Chapters
+        </a>
     <% } else if(chapters.length === 1) { %>
         <%= chapters.at(0).get("asset_path") %>
     <% } %>
     <a href="#" class="view"><%= gettext("view in course") %></a>
     <button class="edit"><%= gettext("Edit") %></button>
     <button class="delete"><%= gettext("Delete") %></button>
+    <% if(showChapters) { %>
+    <hr>
+    <ol class="chapters">
+      <% chapters.each(function(chapter) { %>
+        <li><span class="chapter-name"><%= chapter.get('name') %></span>
+            <span class="chapter-asset-path"><%= chapter.get('asset_path') %></span>
+        </li>
+      <% }) %>
+    </ol>
+    <% } %>
 </li>

cms/templates/textbooks.html

@@ -29,6 +29,7 @@ window.UPLOAD_ASSET_CALLBACK_URL = "${upload_asset_callback_url}"
 CMS.Models.Textbook = Backbone.Model.extend({
     defaults: {
         name: "",
+        showChapters: false
     },
     initialize: function() {
         this.chapters = new CMS.Collections.ChapterSet;
@@ -45,7 +46,9 @@ CMS.Views.TextbookShow = Backbone.View.extend({
     },
     events: {
         "click .edit": "editTextbook",
-        "click .delete": "removeSelf"
+        "click .delete": "removeSelf",
+        "click .show-chapters": "showChapters",
+        "click .hide-chapters": "hideChapters"
     },
     render: function() {
         var attrs = $.extend({}, this.model.attributes);
@@ -60,6 +63,14 @@ CMS.Views.TextbookShow = Backbone.View.extend({
     removeSelf: function(e) {
         if(e && e.preventDefault) { e.preventDefault(); }
         this.model.collection.remove(this.model);
+    },
+    showChapters: function(e) {
+        if(e && e.preventDefault) { e.preventDefault(); }
+        this.model.set('showChapters', true);
+    },
+    hideChapters: function(e) {
+        if(e && e.preventDefault) { e.preventDefault(); }
+        this.model.set('showChapters', false);
     }
 })
 CMS.Views.TextbookEdit = Backbone.View.extend({