Ruby on Rails Tutorial — Heroku API Deployment

Alex Merced Coder
2 min readJan 7, 2021


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This tutorial requires that you’ve already installed

  • ruby
  • rails

Create a new rails project

rails new dogs --api -d postgresql

cd into the dogs folder

Configuring your Database

Assuming you have a local postgres server make sure you write your database.yml like so. Make sure the username and password matches your local postgres user.

default: &default
adapter: postgresql
encoding: unicode
pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
# Make sure the below reflects your local postgres user
port: 5432
host: localhost
username: test5
password: test5
<<: *default
database: mice_development
<<: *default
database: mice_test
<<: *default
url: <%= ENV['DATABASE_URL'] %>

Uncomment gem 'rack-cors' in your gemfile then run bundle install

Edit your config/initializers/cors.rb to look like so. This will allow all origins to make requests, customize to your liking.

Rails.application.config.middleware.insert_before 0, Rack::Cors do
allow do
origins '*'
resource '*',
headers: :any,
methods: [:get, :post, :put, :patch, :delete, :options, :head]

Create a quick API

Run the following commands for a basic dogs api…

rails g scaffold dog name:string age:integer breed:string

rails db:migrate

Add the following in db/seeds.rb

Dog.create(name: "Sparky", age: 5, breed: "Bulldog")
Dog.create(name: "Spot", age: 5, breed: "Dalmation")
Dog.create(name: "Goldy", age: 5, breed: "Golden Retriever")

run the command rails db:seed

Test the Api

rails server

Go to localhost:3000/dogs to see if our dogs are there, if so we are ready to deploy.

Deploy to Heroku

  • push your code to github (make sure the root of the repo is the same folder as the gemfile)
  • create a new heroku project and connect it to your github repo
  • using the heroku cli run the following commands

heroku run rails db:migrate --app=youAppName && heroku run rails db:seed --app=youAppName *make sure to replace yourAppName with the name of your heroku project

That’s it, go to https://HEROKUURL/dogs

and you should see your dogs!!!



Alex Merced Coder

Alex Merced is a Developer Advocate for Dremio and host of the Web Dev 101 and Datanation Podcasts.