sub new {
  my ( $class, $mango_connect, $sharpener_db ) = @_;
  my $mango_instance = Mango->new( $mango_connect );
  my $sharpener_db = $mango_instance->db($sharpener_db);
  my $collections = (
    'DashboardsColl' => $sharpener_db->collection('dashboards'),
    'MangoInstance'  => $mango_instance,
    'MetricsColl'    => $sharpener_db->collection('metrics'),
    'SharpenerDb'    => $sharpener_db
  );
  bless $collections, $class;
  return $collections;
}