lib/MyAppMerge.pm 

my $table_handlers = [     # row_count_estimates
    al_links                        => [ 'skip_empty' ],
    schema_migrations               => [ 'skip' ],  # manual

    issue_statuses                  => [ 'skip_subset' ],

    users             => [ 'build_mapping', 'email' => 'id' ],

    projects          => [ 'mapping_table', 'project_desc' => 'id' ],