LoadError: Could not find matching strategy for :salesforce.

[rafaelricci]

I'm updating an omniauth-salesforce to omniauth-salesforce-ruby and I'm getting this error:

LoadError: Could not find matching strategy for :salesforce. You may need to install an additional gem (such as omniauth-salesforce).
Caused by: NameError: uninitialized constant OmniAuth::Strategies::Salesforce

implementation code:

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :salesforce, ENV['MY_SALESFORCE_KEY'], ENV['MY_SALESFORCE_SECRET'], setup: true
  provider OmniAuth::Strategies::SalesforceSandbox, ENV['MY_SALESFORCE_KEY'], ENV['MY_SALESFORCE_SECRET']
end

Can you help me? I'm available if you have any questions