feat: add epoch distribution info generation task

lib/tasks/migration/fill_epoch_distribution_info_to_epoch_statistics.rake

@@ -0,0 +1,25 @@
+class EpochDistributionInfoGenerator
+  include Rake::DSL
+
+  def initialize
+    namespace :migration do
+      desc "Usage: RAILS_ENV=production bundle exec rake migration:fill_epoch_distribution_info"
+      task fill_epoch_distribution_info: :environment do
+        latest_epoch_statistic = EpochStatistic.order(epoch_number: :desc)[0]
+        epoch_statistic_generator = Charts::EpochStatisticGenerator.new(latest_epoch_statistic.epoch_number)
+
+        block_time_distribution = epoch_statistic_generator.send(:block_time_distribution)
+        epoch_time_distribution = epoch_statistic_generator.send(:epoch_time_distribution)
+        epoch_length_distribution = epoch_statistic_generator.send(:epoch_length_distribution)
+
+        latest_epoch_statistic.update(block_time_distribution: block_time_distribution, epoch_time_distribution: epoch_time_distribution, epoch_length_distribution: epoch_length_distribution)
+        puts "done"
+      end
+    end
+  end
+
+  private
+
+end
+
+EpochDistributionInfoGenerator.new