Create basic user model
Added rake task (app:user:create) to create a new user and api-key
Added User#display
Install mocha gem
Add authentication code to base API controller
Added authentication to V0 API controller
Add AuditLogEntry model
Add audit logging when updating paper's metadata
Updated todo list
Merge pull request #6 from ploslabs/feature/authentication_and_authorization

Feature/authentication and authorization
Merge branch 'master' into feature/citation_groups_model

Conflicts:
	db/schema.rb