jQuery UI sortable plugin added to the app.

src/main/twirl/gitbucket/core/main.scala.html

@@ -18,8 +18,12 @@
     <link href="@helpers.assets("/vendors/AdminLTE-2.3.8/css/AdminLTE.min.css")" rel="stylesheet">
     <link href="@helpers.assets("/vendors/AdminLTE-2.3.8/css/skins/skin-blue.min.css")" rel="stylesheet">
     <link href="@helpers.assets("/vendors/font-awesome-4.6.3/css/font-awesome.min.css")" rel="stylesheet">
+    <link href="@helpers.assets("/vendors/jquery-ui/jquery-ui.min.css")" rel="stylesheet">
+    <link href="@helpers.assets("/vendors/jquery-ui/jquery-ui.structure.min.css")" rel="stylesheet">
+    <link href="@helpers.assets("/vendors/jquery-ui/jquery-ui.theme.min.css")" rel="stylesheet">
     <link href="@helpers.assets("/common/css/gitbucket.css")" rel="stylesheet">
     <script src="@helpers.assets("/vendors/jquery/jquery-1.12.2.min.js")"></script>
+    <script src="@helpers.assets("/vendors/jquery-ui/jquery-ui.min.js")"></script>
     <script src="@helpers.assets("/vendors/dropzone/dropzone.js")"></script>
     <script src="@helpers.assets("/common/js/validation.js")"></script>
     <script src="@helpers.assets("/common/js/gitbucket.js")"></script>

src/main/webapp/assets/vendors/jquery-ui/jquery-ui.structure.min.css

@@ -0,0 +1,5 @@
+/*! jQuery UI - v1.12.1 - 2017-06-03
+* http://jqueryui.com
+* Copyright jQuery Foundation and other contributors; Licensed MIT */
+
+.ui-sortable-handle{-ms-touch-action:none;touch-action:none}