How can I insert an object in an array of objects in ruby?

I need to print uniq results inside an array. To test this I need to insert an object inside my array.

array = [#<Card id: 394034, cards_config_id: nil>, #<Card id: 394033, cards_config_id: nil>, #<Card id: 394032, cards_config_id: nil>, #<Card id: 394035, cards_config_id: nil>]

I need to insert another Card object to test uniqueness. Something like this array.uniq &:id

I know this is wrong but how can I achieve this ?

array << Card id:394034, cards_config_id: nil>