Card support on trellobo

Hi, i've added support for creating and moving cards between lists, also assigning users to cards and the ability to mail a resume of a card to trellobo. Please review what i've done and let me know if you have any comments. 

PD: all cards operations are squashed into only one commit. To see more git history on this work please refer to the branch named: adding_support_for_card_operations 

Best Regards, 
Damian.