Display the lock icon for private repositories.

src/main/twirl/header.scala.html

@@ -1,8 +1,12 @@
 @(active: String, repository: service.RepositoryService.RepositoryInfo)(implicit context: app.Context)
 @import context._
 @import service.AccountService._
+@import service.RepositoryService._
 <div class="head">
   <a href="@path/@repository.owner">@repository.owner</a> / <a href="@path/@repository.owner/@repository.name">@repository.name</a>
+  @if(repository.repository.repositoryType == Private){
+    <i class="icon-lock"></i>
+  }
 </div>
 <table class="global-nav box-header">
   <tr>