Here I'll add some comments along making this small TODO API-only app. I use RubyMine from JetBrains as IDE, and Ubuntu 14.04.4 LTS as dev environment.

Versioning of APIs is skipped for simplicity.

Start a new API-only Rails 5.0 project:

rails new todo_app --api

Add few gems to Gemfile:

gem 'rspec-rails' # for testing with RSpec - TODO

gem 'bcrypt' # password hashing

gem 'active_model_serializers' # model serializer

gem 'rack-cors' # cross domain access

I decided to go for a version with authentication, but without categories handling. This means I will have two models - User and Task.

User model I made without email field for simplicity. Authentication will be handled via token field assigned ONLY once randomly to each user during the creation of the user and stored in the database. Better practice would be to generate this token each time the user logs in, and remove it on logout + add expiration time. Here I made a simple implementation by myself, but one can use already made libraries like Knock, Diverse, Authlogic and others for JWT based authentication. Probably a smart idea would be to cache the token in the Redis so that server will not call database on each request checking if token is correct and/or to which user it is assigned.

rails generate scaffold User username:string password:digest token:string

rails generate migration add_index_to_users_token

Task model is simple with just few fields and reference to User model.

rails generate scaffold Task title:string done:boolean user:references

Create user:

curl -X POST -H "Content-Type: application/json" -d '{"user": {"username": USERNAME,"password": PASSWORD } } ' "http://localhost:3000/users/"

Login user:

curl -X POST -H "Content-Type: application/json" -d '{"user": {"username": USERNAME,"password": PASSWORD } } ' "http://localhost:3000/login"

Get all users:

curl -H "Authorization: Token token=TOKEN" http://localhost:3000/users

Deployed to Heroku:

https://guarded-peak-24627.herokuapp.com

Still TODO (ironically), just for fun:

• testing with RSpec
• use fixtures for unit testing
• refactor unit tests for controllers
• make a simple client in VueJS
• implement categories