uses a journal cache to render the history

See the comment for some details.

We should think about moving this into a different place like the
controller or the User.current. Doing so would provide us with a request
cache that can be reused for multiple purposes.

However this might cause serious memory issues.

app/views/issues/_history.rhtml

@@ -1,6 +1,15 @@
+<%# Uses a cache to render the history. The placeing of this object
+is somewhat arbitrary. The important point is that it is not instantiated within
+a journal as the cache could then not be used between all of an issue's journals. %>
+
+<% @journal_cache = Acts::Journalized::JournalObjectCache.new %>
+
 <% for journal in journals %>
-  <%= render_journal issue, journal, :edit_permission => :edit_issue_notes,
-      :edit_own_permission => :edit_own_issue_notes %>
+  <%= render_journal issue,
+                     journal,
+                     :edit_permission => :edit_issue_notes,
+                     :edit_own_permission => :edit_own_issue_notes,
+                     :cache => @journal_cache %>
   <%= call_hook(:view_issues_history_journal_bottom, { :journal => journal }) %>
 <% end %>