Add "Show only selected branch" checkbox

app/views/graph/_head.html.haml

@@ -4,6 +4,14 @@
 .clearfix
   .pull-left
     = render partial: 'shared/ref_switcher', locals: {destination: 'graph'}
+  .pull-left
+    = form_tag project_graph_path(@project, @id), method: :get do |f|
+      .control-group
+        = label_tag :filter_ref, "Show only selected ref", class: 'control-label light'
+        .controls
+          = check_box_tag :filter_ref, 1, @options[:filter_ref]
+    - @options.each do |key, value|
+      = hidden_field_tag(key, value, id: nil) unless key == "filter_ref"
 
   .search.pull-right
     = form_tag project_graph_path(@project, @id), method: :get do |f|

app/views/graph/show.html.haml

@@ -7,6 +7,9 @@
 
 :javascript
   var branch_graph;
+  $("#filter_ref").click(function() {
+    $(this).closest('form').submit();
+  });
   branch_graph = new BranchGraph($("#holder"), {
     url: '#{project_graph_path(@project, @ref, @options.merge(format: :json))}',
     commit_url: '#{project_commit_path(@project, 'ae45ca32').gsub("ae45ca32", "%s")}',