Refactor: add Studio and reference from LuminaUser
Refactor: customer_of now refers to a Studio instance
Refactor: add FIXMEs to document pending tasks
Refactor: Rename Album to Session
Refactor: fix doc and related_name
Refactor: add Customer
Refactor: add attributes to Customer
Refactor: add customer attribute to Session
Refactor: add FIXME
Refactor: rename attributes of LuminaUser
Add docs to models
Refactor: add FIXMEs
Refactor: rename SharedAlbum to SharedSessionByEmail
Refactor: FIX admin
Refactor: remove user and add studio in Session
Refactor: more refactoring and docs
Refactor: add docs
Remove the word 'FIXME' in some commets
Add FIXME to methods pending to be refactored
Remove commented code