myapp/config/database.yml
defaults: &defaults
encoding: unicode
adapter: postgresql
host: <%= ENV.fetch('DB_HOST') { 'localhost' } %>
port: <%= ENV.fetch('DB_PORT') { 5432 } %>
username: <%= ENV.fetch('DB_USERNAME') { system("whoami") } %>
password: <%= ENV.fetch('DB_PASSWORD') { nil } %>
pool: <%= ENV.fetch('RAILS_MAX_THREADS') { 5 } %>
development:
<<: *defaults
database: myapp_dev
test:
<<: *defaults
database: myapp_test
production:
<<: *defaults
database: myapp_prod