Readme update.
Merge branch 'master' of github.com:antico5/library_example
Fix spec mistakes.
Avoid memoization on parsed json body.
Change how the headers are injected in the request.
Update spec status code.
Delete unused specs.
Migrate schema.
Route for borrowing books.
User model implementation.
Book model. Scopes and instance methods.
Clean up controller. Implement index, create and borrow actions.
Authentication and authorization methods.
Readme update: considerations.
Spec for authentication.