Mermaid support in the code app

www/common/diffMarked.js

@@ -7,10 +7,12 @@ define([
     '/common/media-tag.js',
     '/common/highlight/highlight.pack.js',
     '/customize/messages.js',
+    '/code/mermaid.js',
+    'css!/code/mermaid.css',
     '/bower_components/diff-dom/diffDOM.js',
     '/bower_components/tweetnacl/nacl-fast.min.js',
     'css!/common/highlight/styles/github.css'
-],function ($, Marked, Hash, Util, h, MediaTag, Highlight, Messages) {
+],function ($, Marked, Hash, Util, h, MediaTag, Highlight, Messages, Mermaid) {
     var DiffMd = {};
 
     var DiffDOM = window.diffDOM;
@@ -67,6 +69,14 @@ define([
 
     var mediaMap = {};
 
+    renderer.code = function (code, language) {
+        if(language == 'mermaid' && (code.match(/^sequenceDiagram/) || code.match(/^graph/))) {
+            return '<pre class="mermaid">'+code+'</pre>';
+        } else {
+            return '<pre><code>'+code+'</code></pre>';
+        }
+    };
+
     renderer.heading = function (text, level) {
         var i = 0;
         var safeText = text.toLowerCase().replace(/[^\w]+/g, '-');
@@ -271,6 +281,9 @@ define([
             throw new Error(patch);
         } else {
             DD.apply($content[0], patch);
+            try {
+                Mermaid.init();
+            } catch (e) { console.error(e); }
             var $mts = $content.find('media-tag:not(:has(*))');
             $mts.each(function (i, el) {
                 $(el).contextmenu(function (e) {