Use a better structure for snapshots

Snapshots should be stored in a better way (more documents rather
than an array/object of snapshots). This change in aquarium reflects
that change in the database.
Order snapshots by descending dates
Use a better structure for snapshots

Snapshots should be stored in a better way (more documents rather
than an array/object of snapshots). This change in aquarium reflects
that change in the database.
Order snapshots by descending dates
Merge branch 'develop'