Speed up swarm imports using multi-threading

ruby_importers/importers/swarm/swarm_coordinates_importer.rb

@@ -8,6 +8,7 @@ module Importers
       all = []
 
       swarm.checkins.each do |checkin|
+        all_threads_for_this_checkin = []
         timestamp = Time.at(checkin["createdAt"])
         d = swarm.fetch_checkin_detail(checkin)
         next if d.nil?
@@ -40,22 +41,27 @@ module Importers
         }.each do |key, value|
           next if value.to_s.length == 0 # e.g. no category
 
-          insert_row_for_timestamp(
-            timestamp: timestamp,
-            key: key,
-            value: value,
-            type: ["swarmCheckinCoordinatesLat", "swarmCheckinCoordinatesLng", "swarmCheckinTimezone"].include?(key) ? "number" : "text",
-            question: "Swarm coordinates #{key}",
-            source: "importer_swarm",
-            import_id: import_id,
-            matched_date: (timestamp + timezone_offset * 60).to_date
-          )
+          all_threads_for_this_checkin << Thread.new do
+            insert_row_for_timestamp(
+              timestamp: timestamp,
+              key: key,
+              value: value,
+              type: ["swarmCheckinCoordinatesLat", "swarmCheckinCoordinatesLng", "swarmCheckinTimezone"].include?(key) ? "number" : "text",
+              question: "Swarm coordinates #{key}",
+              source: "importer_swarm",
+              import_id: import_id,
+              matched_date: (timestamp + timezone_offset * 60).to_date
+            )
+          end
 
           # For the matched_date I did some investigation on check-ins on the West Coast
           # and also found a bug in the Swarm app, where when they render just the date
           # they forget to use the timezone offset. Used on the example of the Swarm checkin
           # with the ID of "5e496619a526b30008affda7"
         end
+
+        puts "Waiting for threads to be complete..."
+        all_threads_for_this_checkin.each(&:join)
       end
       File.write("tracks.json", JSON.pretty_generate(all))    
     end