Add images paths to meetup json

[paulinaszkudlarek]

Add functionality that will add all images paths to meetup information file (json).

Functionality should :

• find json file with specified meetup,
• add new key with an array "images" as a value ,
• add paths of all images that are placed:
  /public/images/events/{meetup-id}/{image-name}
• images paths could be available in single meetup file and in meetups list file.

result.: