Use named route.

git-svn-id: http://svn.redmine.org/redmine/trunk@15312 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/watchers/_watchers.html.erb

@@ -1,7 +1,7 @@
 <% if User.current.allowed_to?(:add_issue_watchers, watched.project) %>
 <div class="contextual">
 <%= link_to l(:button_add),
-      {:controller => 'watchers', :action => 'new', :object_type => watched.class.name.underscore, :object_id => watched},
+      new_watchers_path(:object_type => watched.class.name.underscore, :object_id => watched),
       :remote => true,
       :method => 'get' %>
 </div>