Rails不会导出到CSV缺少的模板

Question

缺少模板调整/索引，带有{：locale => [：en] 、: formats => [：csv] 、: variants => [] 、: handlers => [：raw，：erb， ：html，：builder，：ruby，：coffee，：jbuilder]}。在以下位置搜索：

尝试安全创建模型的csv时遇到此错误，我正在寻求帮助来解决这个难题。我不是开发人员，我只是为个人工作文件制作了Rails应用程序。

我的模型tuning.rb

class Tuning < ApplicationRecord
has_many :invoices, dependent: :destroy
has_many :pianos
has_many :contacteds
has_many :interests
has_many :expenses, through: :pianos
accepts_nested_attributes_for :pianos
accepts_nested_attributes_for :invoices
accepts_nested_attributes_for :contacteds
accepts_nested_attributes_for :interests
validates :Client, presence: true
validates :Tel, presence: true
validates :Address, presence: true
geocoded_by :Address
after_validation :geocode
def start_time 
self.scheduled_date.start



end

    def index

        @tunings = Tuning.all
    end
def self.to_csv
    CSV.generate do |csv|
      csv << column_names
      all.each do |client|
        csv << client.attributes.values_at(*column_names)
      end
    end
  end

end

my controller: 

    def index

    @tunings = Tuning.all.order('scheduled_date ASC')
    respond_to do |format|
      format.html
      format.csv { render text: @tunings.to_csv }

    @invoices = Invoice.all


  end
   add_breadcrumb "Home", :root_path
    add_breadcrumb "All Tunings"
  end

非常感谢您的投入。谢谢