Add exception notifications when wildcard searches fail

It's unclear if this is a big problem or if we could mitigate failed
wildcard searches by adjusting Xapian's max expansion limit.

This is also changes the  Rails logging level to warn.

lib/typeahead_search.rb

@@ -1,5 +1,7 @@
 class TypeaheadSearch
 
+  include ConfigHelper
+
   attr_accessor :query, :model, :page, :per_page, :wildcard, :run_search
 
   def initialize(query, opts = {})
@@ -22,7 +24,12 @@ def xapian_search
       xapian_search = run_query
     rescue ActsAsXapian::UnhandledRuntimeError => e
       # Wildcard expands to too many terms
-      Rails.logger.info "Wildcard query '#{query}' caused: #{e.message.force_encoding('UTF-8')}"
+      Rails.logger.warn "Wildcard query '#{query}' caused: #{e.message.force_encoding('UTF-8')}"
+
+      if send_exception_notifications?
+        ExceptionNotifier.notify_exception(e, env: options)
+      end
+
       @wildcard = false
       xapian_search = run_query
     end

spec/lib/typeahead_search_spec.rb

@@ -246,6 +246,12 @@ def search_bodies(xapian_search)
         )
       end
 
+      it 'sends a notification' do
+        TypeaheadSearch.new('dog', options).xapian_search
+        mail = ActionMailer::Base.deliveries.first
+        expect(mail.subject).to match(/dog\* expands to more than 1 term/)
+      end
+
     end
   end
 end