Add offline model and "new" form/controller

app/controllers/contests_controller.rb

@@ -1,6 +1,6 @@
 class ContestsController < ApplicationController
   before_action :set_contest, only: %i[ destroy edit show update ]
-  skip_before_action :require_authentication, only: %i[ scoreboard ]
+  skip_before_action :require_authentication, only: %i[ scoreboard offline_new ]
 
   def index
     authorize :contest
@@ -99,6 +99,21 @@ class ContestsController < ApplicationController
     render :scoreboard
   end
 
+  def offline_new
+    @contest = Contest.find_by(slug: params[:id])
+    unless @contest && @contest.public
+      skip_authorization
+      not_found and return
+    end
+    authorize :contest
+
+    I18n.locale = @contest.lang
+
+    @title = I18n.t("contests.scoreboard.title", name: @contest.name)
+
+    @offline = Offline.new
+  end
+
   private
 
   def set_badges