Fixes #13 - POST /tcos/{tco_id}/attendees/{id}/like

Please note that for all GET/POST attendee/album/event likes, what I implemented is that **something** is liked.
I am not sure if this is the required behavior or it should be **someone** likes **something**. In the later case we will need to update all the endpoints to take {attendee_id} as an additional input.

Let me know if this implementation is ok.