* add party_shares table and model with associations
* add party share errors and blueprint
* add party shares controller and routes
* include shared parties in listings and show
* add party share factory and model specs
* add party shares controller specs
* include shares in party response for owners
* add crew shared_parties endpoint
- create crew_invitations table with status enum
- add CrewInvitation model with accept/reject flow
- add CrewInvitationsController for send/accept/reject
- add invitation error classes
- add invitation routes nested under crews
- add pending invitations endpoint for current user
- 38 passing specs for model and controller
- crews table with name, gamertag, granblue_crew_id, description
- crew_memberships with role enum (member/vice_captain/captain)
- partial unique index ensures one active crew per user
- updated User model with crew associations and helper methods
* Add migrations to add user roles and party visibility.
* Update schema.rb
* Add admin check in User model
* Implement rudimentary visibility of teams
* Adds checks to Party model
* Hides parties from collection views depending on visibility
* Disallows viewing private parties if you're not the owner
* Add a party's visibility to blueprint
* Add admin mode
The API Controller checks if the user is logged in and whether they are an admin, and checks for the X-Admin-Mode header
* Implement admin mode overrides
* Add admin_mode to authorize
* Note to self: Implement user editing by admins
* Fix syntax error with equality in SQL
* Fix syntax error with method name
* Fix bug in who can see restricted parties
* Add privacy control to user profiles
