Documentation added to resources structs
Documentation added to resources structs

Structs MediaCarousel, MediaImage and MediaVideo are
now documented as well, explaining what they are

Ref: #2
Signed-off-by: Leonardo Javier Esparis Meza <bd1fd2b25b72989a7818350d55f07406eccc9977@gmail.com>

ljesparis/gostagram,ljesparis/gostagram,ljesparis/gostagram