Bind aggregates over scoped tags to their subtree

CccConventions::TAG_SCOPES maps "update" and "pressemitteilung" to /updates
and "disclosure" to /disclosure. Page.aggregate applies the mapping, so an
aggregate over one of those tags is bounded by its subtree regardless of what
the shortcode says. Tags stay unrestricted; positions are publish-gated.

Both RSS actions call Page.aggregate rather than repeating its tag join.

Empty feeds no longer crash: Atom falls back to the current time for the
required <updated>, and the optional dc:date is omitted.

1 files changed, 1 insertions, 1 deletions

diff --git a/app/views/rss/updates.xml.builder b/app/views/rss/updates.xml.builder
index 27845c4c..f261de89 100644
--- a/app/views/rss/updates.xml.builder
+++ b/app/views/rss/updates.xml.builder
@@ -4,7 +4,7 @@ xml.feed(:xmlns => "http://www.w3.org/2005/Atom", "xml:base" => @host) do
   xml.title("Chaos Computer Club Updates")
   xml.link(:href => "https://www.ccc.de/")
   xml.link(:rel => "self", :href => "#{@host}/rss/updates.xml")
-  xml.updated(@items.first.published_at.xmlschema)
+  xml.updated((@items.first&.published_at || Time.now).xmlschema)
   xml.author do
     xml.name("Chaos Computer Club e.V.")
   end