fix new milestone button visibility

templates/repo/issue/milestones.tmpl

@@ -4,9 +4,11 @@
 	<div class="ui middle page grid body">
 		<div class="navbar">
 			{{template "repo/issue/navbar" .}}
+			{{if .IsRepositoryAdmin}}
 			<div class="ui right floated secondary menu">
 				<a class="ui green button" href="{{$.RepoLink}}/milestones/new">{{.i18n.Tr "repo.milestones.new"}}</a>
 			</div>
+			{{end}}
 		</div>
 		<div class="ui divider"></div>
 		{{template "repo/issue/alert" .}}
@@ -22,7 +24,6 @@
 			  </a>
 			</div>
 		</div>
-
 		
 		<div class="sixteen wide column">
 			<div class="milestone list">