The application configuration file is /config/application.rb.
Here you can set
Timezone, e.g. config.time_zone = 'Pacific/Auckland'
Different environment settings are available in /config/environments
Specifically, these are
Production: /config/environments/production.rb
Development: /config/environments/development.rb
Staging: /config/environments/staging.rb
Test: /config/environments/test.rb
To set up your site, you will at least need to configure the procution configuration, in particular:
Mail server domain: config.action_mailer.smtp_settings.domain
Mail server URL host: config.action_mailer.default_url_options.host
Mail server asset host: config.action_mailer.asset_host
Optionally set Action Mailer settings (alternatively set in server environment variables, see Heroku)
Action mailer host and protocol: config.action_mailer.default_url_options
Action mailer asset host: config.action_mailer.asset_host
The email address used by the application when sending out emails, including for user authentication and email reminders is set in:
General: /app/mailers/application_mailer.rb
Devise: /config/initializers/devise.rb
Please make sure the email domain coincides with your mail application, eg MailGun