Fix label in form to add own answer

The label text was always in English, and it wasn't associated with any
input field.

The `SecureRandom` part is a quick hack so we don't get duplicate IDs.
Using "your_answer_#{question.id}" might work as well, but right now I'm
not sure if the form is sometimes rendered twice for the same question.

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

@@ -1,5 +1,6 @@
 <%= form_tag(create_answer_question_path(question, token: token), method: :post, remote: true) do %>
-  <label> You can add your own answer</label>
-  <input type="text" class="medium-10" name="answer">
-  <input class="button success" type="submit" value="<%= t("poll_questions.show.add_answer") %>">
+  <% id = "your_answer_#{SecureRandom.hex}" %>
+  <%= label_tag :answer, t("poll_questions.show.your_answer"), for: id %>
+  <%= text_field_tag :answer, nil, class: "medium-10", id: id %>
+  <%= submit_tag t("poll_questions.show.add_answer"), class: "button success" %>
 <% end %>

config/locales/en/general.yml

@@ -701,6 +701,7 @@ en:
     show:
       vote_answer: "Vote %{answer}"
       voted: "You have voted %{answer}"
+      your_answer: "You can add your own answer"
       add_answer: "Add answer"
     description:
       multiple: "You can select a maximum of %{maximum} answers."

config/locales/es/general.yml

@@ -699,6 +699,7 @@ es:
     show:
       vote_answer: "Votar %{answer}"
       voted: "Has votado %{answer}"
+      your_answer: "Puedes añadir tu propia respuesta"
       add_answer: "Añadir respuesta"
     description:
       multiple: "Puedes seleccionar un máximo de %{maximum} respuestas."