DBIx::Class::Helpers3pm

 package MyApp::Schema::Result::Foo_Bar;
 __PACKAGE__->load_components(qw{Helper::JoinTable Core});
 __PACKAGE__->join_table({
    left_class   => 'Foo',
    left_method  => 'foo',
    right_class  => 'Bar',
    right_method => 'bar',
 });
 # define parent class
 package ParentSchema::Result::Bar;
 use strict;
 use warnings;
 use parent 'DBIx::Class';
 __PACKAGE__->load_components('Core');
 __PACKAGE__->table('Bar');
 __PACKAGE__->add_columns(qw/ id foo_id /);
 __PACKAGE__->set_primary_key('id');
 __PACKAGE__->belongs_to( foo => 'ParentSchema::Result::Foo', 'foo_id' );
 # define subclass
 package MySchema::Result::Bar;
 use strict;
 use warnings;
 use parent 'ParentSchema::Result::Bar';
 __PACKAGE__->load_components(qw{Helper::SubClass Core});
 __PACKAGE__->subclass;