Check if user has voted before sign in

app/helpers/polls_helper.rb

@@ -41,4 +41,8 @@ module PollsHelper
     booth.name + location
   end
 
+  def voted_before_sign_in(question)
+    current_user.current_sign_in_at >= question.poll.voters.find_by_user_id(current_user).updated_at
+  end
+
 end

app/views/polls/questions/_answers.html.erb

@@ -1,7 +1,7 @@
 <div class="poll-question-answers">
   <% if can? :answer, question %>
     <% question.question_answers.each do |answer| %>
-      <% if @answers_by_question_id[question.id] == answer.title %>
+      <% if @answers_by_question_id[question.id] == answer.title && !voted_before_sign_in(question) %>
         <span class="button answered"
               title="<%= t("poll_questions.show.voted", answer: answer.title)%>">
           <%= answer.title %>