Heroku Deploy

../initializers/stripe.rb

Rails.configuration.stripe = {
  publishable_key: Rails.application.credentials.stripe[:publishable_key],
  secret_key: Rails.application.credentials.stripe[:secret_key],
  webhook_secret: Rails.application.credentials.stripe[:webhook_secret],
}
Stripe.api_key = Rails.configuration.stripe[:secret_key]

../config/credentials/production.yml.enc

stripe:
  secret_key: sk_test_xxxx
  publishable_key: pk_test_xxx
  webhook_secret: whsec_xxx

Heroku Config:

PUBLISHABLE_KEY:          pk_test_xxx
SECRET_KEY:               sk_test_xxx
SECRET_KEY_BASE:          xxxxx