Remove fedireads_key field

we have ID

fedireads/templates/snippets/rate_action.html

@@ -4,7 +4,7 @@
     {% for i in '12345'|make_list %}
     <form name="rate" action="/rate/" method="POST" onsubmit="return rate_stars(event)">
         {% csrf_token %}
-        <input type="hidden" name="book" value="{{ book.fedireads_key }}">
+        <input type="hidden" name="book" value="{{ book.id }}">
         <input type="hidden" name="rating" value="{{ forloop.counter }}">
         <button type="submit" class="icon icon-star-{% if book|rating:user < forloop.counter %}empty{% else %}full{% endif %}">
             <span class="hidden-text">{{ forloop.counter }} star{{ forloop.counter | pluralize }}</span>