Normalize intro node in Summary parsing

lib/parse/summary.js

@@ -94,18 +94,35 @@ function parseChapter(nodes, nums) {
     });
 }
 
+function defaultChapterList(chapterList) {
+    var first = _.first(chapterList);
+
+    var chapter = parseChapter(first, [0]);
+
+    // Already have README node, we're good to go
+    if(chapter.path === 'README.md') {
+        return chapterList;
+    }
+
+    return [
+        [ { type: 'text', text: '[Introduction](README.md)' } ]
+    ].concat(chapterList);
+}
+
 function parseSummary(src) {
     var nodes = marked.lexer(src);
 
     // Get out list of chapters
-    var chapterList = filterList(nodes);
+    var chapterList = listSplit(
+        filterList(nodes),
+        'list_item_start', 'list_item_end'
+    );
 
     // Split out chapter sections
-    var chapters = _.chain(listSplit(chapterList, 'list_item_start', 'list_item_end'))
+    var chapters = defaultChapterList(chapterList)
     .map(function(nodes, i) {
-        return parseChapter(nodes, [i + 1]);
-    })
-    .value();
+        return parseChapter(nodes, [i]);
+    });
 
     return {
         chapters: chapters