This Rails app is part of the RealWorld project.
You might also check Laravel version of this app.
See how the exact same Medium.com clone (called Conduit) is built using different frontends and backends. Yes, you can mix and match them, because they all adhere to the same API spec
Make sure you have Ruby and Rails installed on your computer.
Clone the repo and enter the project folder
git clone https://github.com/alexeymezenin/ruby-on-rails-realworld-example-app
cd ruby-on-rails-realworld-example-app
Install gems
bundle install
Execute migrations
rails db:migrate
Run the web server
rails server
That's it. Now you can use the api, i.e.
http://127.0.0.1:3000/api/articles