• Make an account at heroku.com
• Download & install Postgresql

• Log into your Heroku account
• Click 'New' --> 'Create new app'
• Name your application

• Choose Heroku git or Github

• Group your Gemfile into development and production
• Move sqlite3 into the development group (along with other gems that are just used for development)

group :development do
  gem 'sqlite3', '~> 1.3.6'
  gem 'tux'
  gem 'pry'
  gem 'shotgun'
end

• Add postgresql to the production group

group :production do
  gem 'pg', '~> 0.20'
end

• delete the gemfile.lock and run bundle install

Create a config/database.yml file:

# config/database.yml
development:
  adapter: sqlite3
  encoding: unicode
  database: db/development.sqlite3
  pool: 5
production:
  adapter: postgresql
  encoding: unicode
  pool: 5

and we'll need to update our config/environment.rb file to use this file to establish a connection to our DB. To do that, replace these lines

# config/environment.rb
# ...

ActiveRecord::Base.establish_connection(
  :adapter => "sqlite3",
  :database => "db/#{ENV['SINATRA_ENV']}.sqlite"
)

with

set :database_file, "./database.yml"

• Add the gem 'foreman' to your gemfile
• Create a Procfile with the following code:

web: bundle exec thin start -p $PORT
release: bundle exec rake db:migrate

• This tells Heroku how to start the server and to run migrations before releasing a build

• Go to your app settings on Heroku and set the following variables:
  • SINATRA_ENV = production
  • SESSION_SECRET = 335673ae2a1c5cccec147456
• Ensure your local .env variables only load in development so they don't override the Heroku variables:
  • In your config/environment.rb:

  Dotenv.load if ENV['SINATRA_ENV'] == "development"
  

• git add .
• git commit -m "configure app for heroku"
• git push origin master
• Go to heroku and deploy your master branch

When I updated my ruby version I also installed bundler v2. Heroku wants an older version of bundler (1.15.2) when I do the deployment, so I had to install it as well and then figure out how to use it to generate the Gemfile.lock.

gem install bundler -v 1.15.2
bundle _1.15.2_ install

• Heroku Hosting Example Video
• Additional Guidelines