Don't name the datasource db

[joesepi]

Naming the datasource db is confusing because even though we are connected to Cloudant, when we run lb model, it looks like we are using the in memory datastore

➜  band-app git:(master) ✗ lb model
? Enter the model name: band
? Select the datasource to attach band to: db (memory)
? Select model's base class PersistedModel
? Expose band via the REST API? Yes
? Custom plural form (used to build REST URL): 
? Common model or server only? common