Deck Service (URL scheme, MongoDB schema)

Background

We should reach final decisions on the URL scheme used by slides and decks, and the collections used by MongoDB for storage.

Issues:

1. During the developers meeting, Ali Khalili and Marios Meimaris discussed how the URL scheme should reflect slide/deck IDs and their respective revision IDs. The suggestion is to use the format 
   item_id-revision_number. For example, {57920599593e64b82e0c1219-1} refers to revision "1" of deck "57920599593e64b82e0c1219". The decision should be uniformly applied to all related services (e.g. activities, deck, content revisioning etc.).
2. During the same meeting, Ali Khalili, Marios Meimaris, and Kurt Junghanns suggested that we used one collection (instead of two collections currently used) for storing all items in MongoDB. This was in part due to some technical restrictions imposed by the platform's architecture. A final decision needs to be made for this as well. 

Action items