Use 6 month cache for items that don't really need to expire

bookwyrm/templates/snippets/shelve_button/shelve_button.html

@@ -3,7 +3,8 @@
 {% load cache %}
 
 {% if request.user.is_authenticated %}
-{% cache None shelve_button request.user.id book.id %}
+{# 6 month cache #}
+{% cache 15552000 shelve_button request.user.id book.id %}
 
 {% with book.id|uuid as uuid %}
 {% active_shelf book as active_shelf %}