update template

templates/haproxy_backend_rule.erb

@@ -15,7 +15,7 @@ balance   <%= @be_balance %>
 <% end -%>
 <% if @be_option_array and !@be_option_array.empty? -%>
 <% @be_option_array.each do |be_option| -%>
-server <%= be_option %>
+option    <%= be_option %>
 <% end -%>
 <% end -%>
 <% if @be_server_name_array and !@be_server_name_array.empty? -%>