Html 如何在selecttagruby中添加提示

如何在此下拉列表中添加提示：“选择预算行”

.html.slim代码

select[name="invoice[budget_line_id]" id="invoice_budget_line_id"]
 - BudgetLine.all.each do |budget_line|
   - if budget_line.budget_balance>=@invoice.total_amount
     |  <option class="color-1" value="
     = budget_line.id
     | ">
     = budget_line.description
   - else
     |  <option class="color-2" value="
     = budget_line.id
     | ">
     = budget_line.description
     = '[ Insufficient budget balance]'

选择[name=“发票[预算行\ id]”id=“发票\预算行\ id”]
-BudgetLine.all.each do |预算|行|
-如果预算行.预算余额>=@invoice.total\u金额
|  
=预算\行说明
-否则
|  
=预算\行说明
='[预算余额不足]'

只需添加另一个选项即可。