02) helloRest

📋 RESTful api example

HTTP method	uri	description
GET	/api/users	returns a list of users
GET	/api/users/1	returns the user with ID 1
POST	/api/users	creates a new user
PUT	/api/users/3	updates the user with ID 3
DELETE	/api/users/4	deletes the user with ID 4
DELETE	/api/users	deletes all the users

uri로 자원을 식별, HTTP 메서드로 CRUD 실행.