Add zonefile generation procedure

app/controllers/admin/zonefile_settings_controller.rb

@@ -0,0 +1,30 @@
+class Admin::ZonefileSettingsController < ApplicationController
+  before_action :set_zonefile_setting, only: [:update, :edit]
+  def index
+    @zonefile_settings = ZonefileSetting.all
+  end
+
+  def edit
+    @zonefile_setting = ZonefileSetting.find(params[:id])
+  end
+
+  def update
+    if @zonefile_setting.update(zonefile_setting_params)
+      flash[:notice] = I18n.t('shared.record_updated')
+      redirect_to admin_zonefile_settings_path
+    else
+      flash.now[:alert] = I18n.t('shared.failed_to_update_record')
+      render 'edit'
+    end
+  end
+
+  private
+
+  def set_zonefile_setting
+    @zonefile_setting = ZonefileSetting.find(params[:id])
+  end
+
+  def zonefile_setting_params
+    params.require(:zonefile_setting).permit(:ttl, :refresh, :retry, :expire, :minimum_ttl, :email)
+  end
+end