[#4604] Add an admin panel for the rate caches

lib/redmine_rate/hooks/view_layouts_base_html_head_hook.rb

@@ -0,0 +1,9 @@
+module RedmineRate
+  module Hooks
+    class ViewLayoutsBaseHtmlHeadHook < Redmine::Hook::ViewListener
+      def view_layouts_base_html_head(context={})
+        return content_tag(:style, "#admin-menu a.rate-caches { background-image: url('#{image_path('database_refresh.png', :plugin => 'redmine_rate')}'); }", :type => 'text/css')
+      end
+    end
+  end
+end