fix omniauth link generation. (#74)

template.rb

@@ -213,7 +213,7 @@ def add_multiple_authentication
 
     template = """
     env_creds = Rails.application.credentials[Rails.env.to_sym] || {}
-    %w{ facebook twitter github }.each do |provider|
+    %i{ facebook twitter github }.each do |provider|
       if options = env_creds[provider]
         config.omniauth provider, options[:app_id], options[:app_secret], options.fetch(:options, {})
       end