Maybe/app/models/concerns/providable.rb

# `Providable` serves as an extension point for integrating multiple providers.
# For an example of a multi-provider, multi-concept implementation,
# see: https://github.com/maybe-finance/maybe/pull/561

module Providable
  extend ActiveSupport::Concern

  class_methods do
    def exchange_rates_provider
      api_key = ENV["SYNTH_API_KEY"]

      if api_key.present?
        Provider::Synth.new api_key
      else
        nil
      end
    end

    def git_repository_provider
      Provider::Github.new
    end
  end
end