Remove unused add_question action from admin polls controller

Since commit adf18ee756  this action no longer makes sense.

app/controllers/admin/poll/polls_controller.rb

@@ -42,18 +42,6 @@ class Admin::Poll::PollsController < Admin::Poll::BaseController
     end
   end
 
-  def add_question
-    question = ::Poll::Question.find(params[:question_id])
-
-    if question.present?
-      @poll.questions << question
-      notice = t("admin.polls.flash.question_added")
-    else
-      notice = t("admin.polls.flash.error_on_question_added")
-    end
-    redirect_to admin_poll_path(@poll), notice: notice
-  end
-
   def booth_assignments
     @polls = Poll.current.created_by_admin
   end

app/models/abilities/administrator.rb

@@ -83,7 +83,7 @@ module Abilities
 
       can [:index, :create, :update, :destroy], Geozone
 
-      can [:read, :create, :update, :destroy, :add_question, :booth_assignments], Poll
+      can [:read, :create, :update, :destroy, :booth_assignments], Poll
       can [:read, :create, :update, :destroy, :available], Poll::Booth
       can [:search, :create, :index, :destroy], ::Poll::Officer
       can [:create, :destroy, :manage], ::Poll::BoothAssignment

config/locales/en/admin.yml

@@ -1103,9 +1103,6 @@ en:
         table_title: "Title"
         edit_answers: Edit answers
         see_proposal: "(See proposal)"
-      flash:
-        question_added: "Question added to this poll"
-        error_on_question_added: "Question could not be assigned to this poll"
       destroy:
         alert: "This action will remove the poll and all its associated questions."
         success_notice: "Poll deleted successfully"

config/locales/es/admin.yml

@@ -1102,9 +1102,6 @@ es:
         table_title: "Título"
         edit_answers: Editar respuestas
         see_proposal: "(Ver propuesta)"
-      flash:
-        question_added: "Pregunta añadida a esta votación"
-        error_on_question_added: "No se pudo asignar la pregunta"
       destroy:
         alert: "Esta acción eliminará la votación y todas sus preguntas asociadas."
         success_notice: "Votación eliminada correctamente"

config/routes/admin.rb

@@ -141,7 +141,6 @@ namespace :admin do
   scope module: :poll do
     resources :polls do
       get :booth_assignments, on: :collection
-      patch :add_question, on: :member
 
       resources :booth_assignments, only: [:index, :show, :create, :destroy] do
         get :search_booths, on: :collection