why is the ps3 left out

[mrgreatness71]

[list=][/list]I've enjoyed watching YouTube videos and twitch streams on the game prison architect for a long time I can't play the game since I only have a ps3 and don't have money for a ps4 or a PC.So when the devs announced a console edition of the game I got really excited until I saw a list of the consoles that the game will be on Ps4,Xbox one,Xbox 360 but the ps3 is left out for whatever reason but I would just like to know why there is not going to be a ps3 edition but there will be an Xbox 360 version.