update gitignore
refactor book#print to inject IOHelper
refactor books#print to inject IOHelper, move inital book list
cleanup actions test, use injected IOHelper to deal with all IO operation
refactor Actions to use injected IOHelper
refactor biblioteca main app to use dependency injection
update .gitignore
add user model
add users persistence
add session model
add login action
add view user info action
integrate login & view user info to main app
remove singleton pattern from books & users collection
fix books collection test
add rules on scope method
disable add object on scoped collections
remove window newlines
require login to borrow/return book
add borrowed_by scope