Blob entry migration util

Rakefile

@@ -37,10 +37,17 @@ end
 namespace :blob_entries do
   task :export_samples => :environment do
     limit = ENV["limit"]&.to_i || raise("need 'limit' (num)")
-    out = ENV["out"] || raise("need 'out' (file path, .json encoded)")
-    BlobEntrySampleExporter.new.export_samples(limit, out)
+    outfile = ENV["outfile"] || raise("need 'outfile' (file path, .json encoded)")
+    BlobEntrySampleExporter.new.export_samples(limit, outfile)
   end
   task :import_samples => :environment do
+    infile = ENV["infile"] || raise("need 'infile' (file path, .json encoded)")
+    BlobEntrySampleExporter.new.import_samples(infile)
+  end
+  task :migrate_entries => :environment do
+    start_at = ENV["start_at"]
+    batch_size = ENV["batch_size"]&.to_i || 64
+    BlobEntrySampleExporter.new.migrate_blob_entries(start_at, batch_size)
   end
 end