<%= f.label :root_domain ,"Root Domain", :class => "control-label muted" %>
<%= select_tag :root_domain,
options_for_select((SiteServer.where(:server_name=>server_types.first).first.domain_names.collect{ |u| [u, u] } rescue [])),
:class => "root_domain" %>
<%= button_tag 'add root domain',:type => 'button', :id => 'add_root_domain',class: 'btn btn-info',:style => 'margin-top: 1em;' %>