added created aggregation

its difficult to see if events from crossref or event datacie have been created lated and where the gaps happen. the occured aggregation only focuses on when the events dates were generated but no when they were captured. this aggregation is more useful to identify problems with collection.

app/controllers/events_controller.rb

@@ -185,6 +185,10 @@ def index
         if total > 0
           facet_by_year(response.aggregations.occurred.buckets)
         end
+      created =
+        if total > 0
+          facet_by_year(response.aggregations.created.buckets)
+        end
       prefixes =
         if total.positive?
           facet_by_key(response.response.aggregations.prefixes.buckets)
@@ -219,6 +223,7 @@ def index
           page[:cursor].nil? && page[:number].present? ? page[:number] : nil,
         sources: sources,
         occurred: occurred,
+        createdAt: created,
         prefixes: prefixes,
         "citationTypes" => citation_types,
         "relationTypes" => relation_types,

app/models/event.rb

@@ -263,6 +263,16 @@ def self.query_aggregations
           },
           aggs: { bucket_truncate: { bucket_sort: { size: 10 } } },
       },
+      created: {
+        date_histogram: {
+          field: "created_at",
+          interval: "year",
+          format: "year",
+          order: { _key: "desc" },
+          min_doc_count: 1,
+        },
+        aggs: { bucket_truncate: { bucket_sort: { size: 10 } } },
+    },
       registrants: {
         terms: { field: "registrant_id", size: 10, min_doc_count: 1 },
         aggs: {