Fix a typo on the OmniAuth config (#69)

Author: Rodrigo Argumedo

template.rb

@@ -187,7 +187,7 @@ def add_multiple_authentication
     env_creds = Rails.application.credentials[Rails.env.to_sym] || {}
     %w{ facebook twitter github }.each do |provider|
       if options = env_creds[provider]
-        confg.omniauth provider, options[:app_id], options[:app_secret], options.fetch(:options, {})
+        config.omniauth provider, options[:app_id], options[:app_secret], options.fetch(:options, {})
       end
     end
     """.strip