Reindex SingleDate

Rake task to re-indexing SingleDate Sorl documents.

Note ```Error Couldn't find ActiveFedora::Base with 'id'=xxxxx while indexing xxxxx results```
is result of Solr index data beeing ahead of Fedora data. Issue with local dev env.

The error must not occur on production system.

lib/tasks/index.rake

@@ -47,4 +47,34 @@ namespace :index do
             end
         end
     end
+
+   # bundle exec rake index:all_single_dates
+   desc "re-index all single dates to Solr"
+   task all_single_dates: :environment do
+       # Start timer
+       starting = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+       # Find all places
+       solr = SolrQuery.new
+       query = 'has_model_ssim:SingleDate'
+       dates_response = solr.solr_query(query, 'id,date_tesim', rows=2147483647)
+
+       total = dates_response['response']['numFound'].to_i
+       index = 1
+       dates_response['response']['docs'].map do |date|
+           begin
+               date_id = date['id']
+               date_label = date['date_tesim'][0] unless date['date_tesim'].blank?
+               print "indexing #{index} / #{total}: #{date_id} #{date_label} \n"
+               index += 1
+               ActiveFedora::Base.find(date_id).update_index
+           rescue => e
+               print "Error #{e} while indexing #{date_id} \n"
+           end
+       end
+       # Stop timer
+       ending = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+       seconds = ending - starting
+       hours = seconds/3600
+       print "Total running time: #{hours}h \n"
+   end
 end