Move code in initializers to module for reusing

config/initializers/postgres_partitioning.rb

@@ -35,8 +35,4 @@ unless Gitlab.jh?
   ])
 end
 
-begin
-  Gitlab::Database::Partitioning.sync_partitions unless ENV['DISABLE_POSTGRES_PARTITION_CREATION_ON_STARTUP']
-rescue ActiveRecord::ActiveRecordError, PG::Error
-  # ignore - happens when Rake tasks yet have to create a database, e.g. for testing
-end
+Gitlab::Database::Partitioning.sync_partitions_ignore_db_error

lib/gitlab/database/partitioning.rb

@@ -27,6 +27,12 @@ module Gitlab
           registered_tables.merge(tables)
         end
 
+        def sync_partitions_ignore_db_error
+          sync_partitions unless ENV['DISABLE_POSTGRES_PARTITION_CREATION_ON_STARTUP']
+        rescue ActiveRecord::ActiveRecordError, PG::Error
+          # ignore - happens when Rake tasks yet have to create a database, e.g. for testing
+        end
+
         def sync_partitions(models_to_sync = registered_for_sync)
           Gitlab::AppLogger.info(message: 'Syncing dynamic postgres partitions')