(refs #231)Add anchor icon for headlines in Markdown.

src/main/scala/view/Markdown.scala

@@ -116,8 +116,9 @@ class GitBucketHtmlSerializer(
     val tag = s"h${node.getLevel}"
     val headerTextString = printChildrenToString(node)
     val anchorName = GitBucketHtmlSerializer.generateAnchorName(headerTextString)
-    printer.print(s"<$tag>")
-    printer.print(s"""<a class="anchor" name="$anchorName" href="#$anchorName"></a>""")
+    printer.print(s"""<$tag class="markdown-head">""")
+    printer.print(s"""<a class="markdown-anchor-link" href="#$anchorName"></a>""")
+    printer.print(s"""<a class="markdown-anchor" name="$anchorName"></a>""")
     visitChildren(node)
     printer.print(s"</$tag>")
   }

src/main/webapp/assets/common/css/gitbucket.css

@@ -850,3 +850,18 @@ div.markdown-body table colgroup + tbody tr:first-child td:last-child {
           border-top-right-radius: 4px;
   -moz-border-radius-topright: 4px;
 }
+
+.markdown-head {
+  position: relative;
+}
+
+a.markdown-anchor-link {
+  position: absolute;
+  top: 16px;
+  left: -20px;
+  width: 32px;
+  height: 16px;
+  background-image: url(../images/link.png);
+  background-repeat: no-repeat;
+  display: none;
+}

src/main/webapp/assets/common/js/gitbucket.js

@@ -11,6 +11,26 @@ $(function(){
   $('img[data-toggle=tooltip]').tooltip();
   $('a[data-toggle=tooltip]').tooltip();
 
+  // anchor icon for markdown
+  $('.markdown-head').mouseenter(function(e){
+    $(e.target).children('a.markdown-anchor-link').show();
+  });
+  $('.markdown-head').mouseleave(function(e){
+    var anchorLink = $(e.target).children('a.markdown-anchor-link');
+    if(anchorLink.data('active') != true){
+      anchorLink.hide();
+    }
+  });
+
+  $('a.markdown-anchor-link').mouseenter(function(e){
+    $(e.target).data('active', true);
+  });
+
+  $('a.markdown-anchor-link').mouseleave(function(e){
+    $(e.target).data('active', false);
+    $(e.target).hide();
+  });
+
   // syntax highlighting by google-code-prettify
   prettyPrint();
 });